Types of Enzymes
There are enzymes everywhere in your body, but each one has to perform the task set out for it. Different enzymes work in different forms, at different speeds and with different substrates, which accounts for their variety.
Enzymes are generally classified according to the basic functions they perform. Enzymes that maintain the body's entire metabolism, from the respiratory system to the nervous system, are known as metabolic enzymes. Those groups known as food enzymes are those we absorb together with the foods we eat. The third enzyme group is known as digestive enzymes.
Foodstuffs are broken down and digested, following which countless metabolic processes take place. Metabolism is the name given to the magnificent phenomena taking place in an organism's cells and controlled by enzymes, which direct every metabolic process in the body, bringing about energy and substance production.
ATP production and protein synthesis are two major metabolic reactions. Metabolic enzymes are responsible for taking over and performing all these processes.
With the exception of reproductive cells—which represent only 0.1% of the body's weight—your body is completely different from what it was 12 years before. Over those dozen years, all the cells in your body have been renewed. Your liver is not the liver it once was. In the same way that the blood cells in your circulatory system are not the same ones that existed 10 years ago, neither are the veins through which they flow. Your organs have completely changed and have been renewed, with entirely new cells and molecules. This is of course an astonishing phenomenon.
The most rapid renewal takes place in the epidermis. Every three months, you are given a new skin. The rest of your organs then follow. Over the years, your lungs, kidneys, stomach and all your other organs change—even your eyes that now read these lines. The slowest changes take place in the bone and cartilage. It takes some 10 years for them to change—yet these, too, are finally renewed.
For that reason, there is a constant need for construction in the body. And of the workers engaged in the construction of your body, the most important are the metabolic enzymes. They take in 45 essential nutrients, and convert them into muscles, nerves, bones, blood and organs. At a basic level, they provide the fuel that keeps the cells alive. They enter all the reactions essential for the cell to fulfill its own functions and finish them in a very short space of time. They operate in all vital matters, such as the DNA replication, ATP energy storage, nutrient entry into cells and waste products' exits, and the transmission of electrical signals along the nerves from your sense organs.
Metabolic enzymes are a great blessing bestowed on us by our Lord, important treasuries we enjoy from the moment we are born. They are at work from the moment our lives begin, ready to perform countless functions. These same enzymes will repeat the same tasks time and time again, never stopping. Yet they also have their own life spans.
Enzymes decline in number as we grow older. "Old age" is another term for the decrease in the number of enzymes in the body, and therefore they are unable to function as efficiently as before. Old age is actually an indication not of how much a person has lived, but whether or not the tissues in the body are fully functioning. These tissues depend on the level of enzymes charged with the metabolism of every cell. In other words, the more numerous and functional the enzymes, the more youthful a person's metabolism.56
Of course, the functioning of all these systems and the maintenance of this metabolic order are totally beyond your control. Even if people are young and enjoy a balanced diet, there is nothing they can do to keep their bodies alive if their enzymes do not perform the requisite functions. Cells will continue to die, but will not be renewed, and the organs will increasingly lose their capacity to function. Enzymes are entities that keep one alive. However, do not forget that enzymes are all proteins with no intelligence or consciousness. What we refer to as "metabolism" is nothing more than the functioning of these proteins. There is no point in your trusting in these entities to keep you alive, and it is totally irrational to think that these entities were charged with keeping people alive by chance. We need to realize that it is Allah Who keeps human beings alive. Allah has created all the systems belonging to a human, inspires them to carry out their functions at every moment, creates them at every moment and keeps them under His control at all times.
If a system of yours is interrupted, all you can do is to take the necessary precautions, turn to Allah and seek His assistance. It is Allah, Who keeps you alive, Who will help you. Allah has revealed this in a verse:
Every bite you eat contains important building blocks to be used in the construction of your body. Food that you eat enters with an even more important factor that helps digest the food itself: its own enzymes.
Food enzymes are present in every food we can encounter anywhere on Earth, but they are not resistant to heat. When you cook food, you lose all the enzymes it contains. However, if you eat a raw food, its own enzymes will digest 75% of it. Digestion of any food by its own enzymes makes a very important contribution to the body, since your system need not become fatigued by manufacturing extra enzymes, and it has no need to slow down the production of metabolic enzymes, so essential to the cells, in order to produce digestive enzymes.
Excellent examples of the enzymes constantly active in foods are those present in fruit. In its green state, a banana is 20% starch. When left in a warm place for a while, however, the enzyme amylase converts that 20% starch to 20% sugar. Around a quarter of that sugar is glucose, which the body now has no need to digest.57 Thanks to the enzymes it possesses, fruit completes a major task that is usually carried out in the body before it's even consumed.
Like the banana cited in this example, every fruit or vegetable eaten without being cooked conveys various nutritional benefits without putting the body to any trouble. When you eat a banana, its own enzymes offer it already prepared for your cells by breaking it down—together with the digestion process that begins in the mouth—into small components that can be utilized by your metabolic enzymes, which then assimilate them into the body by converting them into the structural materials needed for cells and organelles.
The enzymes concealed in foodstuffs are able to digest only the particular food in question. For example, the amylase in bananas works only on the banana starch. This enzyme cannot digest the starch in a potato. After you eat a banana, enzymes in the banana cannot help you digest a slice of cooked meat. Nor can these enzymes add any extra enzymes to the body. Their task comes to an end with the digestion of the food in question. An enzyme that enters the body along with food recognizes the food it is going to digest, despite its being broken up in the mouth, and sets itself to digesting it. Given these properties, enzyme molecules literally behave with intelligence. Of course an inanimate molecule cannot really exhibit intelligence—the wisdom we see in the functions that enzymes perform actually belongs to Almighty Allah, Who creates them and places them at the service of living things.
When you eat a cooked food that has lost all its enzymes, the whole job of digestion falls to those enzymes at the ready in your body. The digestive organs, the pancreas in particular, go into extreme production mode to ensure the digestion of food that has entered the stomach by producing large quantities of enzymes. And this production may cause the production rate of metabolic enzymes to fall. This means that insufficient production can be made for the organs to function, renew themselves, and fight disease. Thus the body expends on digesting foods the energy it should use for its own development and defenses.
One of the first researchers into the importance of enzymes in human nutrition, Dr. Edward Howell, founder of the National Enzyme Company, has said this:
By endowing foods with enzymes, Allah has bestowed a most important blessing on us. The way that these enzymes know what they must do as soon as they enter the body, adapt to a mechanism that is completely foreign to them and immediately begin to process the food they need to digest is literally miraculous. These enzymes literally behave in a conscious manner and know that they should go into action the moment the food is broken down. They neither destroy it by acting prematurely, nor go into action hours after it has entered the mouth. They begin working at just the right moment and conclude the whole enterprise at great speed. With the help of these molecules, every fruit you eat is turned into building blocks with which the body can renew itself. Thus it is that your eyes continue to see, your legs to move and your organs to function.
Remember, these unconscious molecules are entities created by Allah and never go wrong because they act under His direction. They act under the infinite intelligence of Allah and have bowed their heads to Him. Allah tells us of this in another verse:
Certain enzymes have been charged with digestion in the body. Lipase breaks down fats, protease breaks down proteins, cellulase breaks down fiber, amylase breaks down starch, lactase breaks down dairy, sucrase breaks down sugars, and maltase breaks down grains. The presence of digestive enzymes is of great importance to metabolic enzymes, because digestion being undertaken by a special enzyme group prevents the metabolism from fatigue. As long as digestive enzymes are present, our bodies' metabolic enzymes can carry out their own tasks alone and need not become involved in such a complex and detailed process as digestion.
For that reason a glorious mechanism operates constantly inside the human body. Whenever you see or smell something to eat, or even if you only think about it, your body triggers the production of digestive enzymes. These stimuli are of great importance, helping ready your body to deal with food before you have even taken a bite.
The process of digestion begins in the mouth, immediately after the food has been chewed. Saliva contains special enzymes, and as soon as they come into contact with food, they start breaking it down. We break down the exterior walls of foods through the chewing process. If the food is raw, the enzymes it contains are released and initiate the digestion process. Carbohydrates begin to be digested in the mouth, when the amylase in saliva breaks the molecular bonds in starch and adds to them the water molecules in saliva. The reason why you feel an increasingly sweet taste when you chew a piece of bread is that the enzymes in your saliva are converting the starch it contains into sugar.
For digestion in the mouth to take place, the necessary pH value is between 6.0 and 7.4, and the enzyme amylase functions best in that pH range. The stomach, on the other hand, is a highly acidic environment, with a pH level of between 1.0 and 3.5—which acidic conditions halt the activity of amylase. For that reason, carbohydrate digestion does not take place in the stomach.
The process of digestion begins in the mouth, then continues in the stomach and the intestines, all of which are rather different from one another in their working conditions. They therefore harbor appropriately different enzymes.
Special Enzymes in the Stomach
Along the digestive route that starts with the mouth, the next major station is the stomach. As with all organs, the stomach contains enzymes that perform special functions. Their very presence in the rather harsh environment of the stomach, which dissolves and breaks down everything that enters it, is of course very surprising. Yet in any case these assistants are specially equipped for working in the stomach, and are another part of this great miracle inside the body.
The stomach is a highly acidic environment, whose walls need to be protected against its own acid. The digestive enzymes also need to be able to survive within it. The stomach meets both conditions. The internal lining of the stomach wall, covered in a mucous layer that comes into contact with food, contains three kinds of cells. One of these secretes hydrochloric acid (HCl), a very powerful acidic solution, strong enough even to dissolve stone. This powerful chemical also plays an important part in the digestive process by breaking down all proteins, particularly meat, entering the stomach, and kills all microbes. Another important characteristic of this acid is that it sets into action pepsinogen, also present in the stomach and which breaks down proteins. Pepsinogen is not secreted when the stomach is empty. Yet when any food reaches the stomach, pepsinogen is converted into the enzyme pepsin by an activator protein, literally as if someone had told it to, and breaks down the foodstuff there.
How can we account for the way that pepsin initiates digestion by recognizing a piece of meat consisting of protein and fats, but does no harm to the stomach, which consists of basically the same protein and fats? Again, how are we to explain the way that hydrochloric acid does not dissolve the stomach itself and the helper enzyme? It is impossible under normal conditions for an enzyme, an acid, molecules, messenger hormones or even the stomach itself to recognize acid's dangers, or the foods that need to be digested, and to take the relevant precautionary measures on a constant, error-free basis at specific times of day. It is Allah Who makes this possible, ensuring that these processes take place uninterruptedly inside all the humans living on Earth, and Who ensures that the molecules receive their instructions, obey them and are compatible with one another.
It is impossible for a molecule to be aware of another molecule by chance, for it to activate by chance, to be aware of dangers by chance and to take appropriate precautionary measures. Each one of these complex structures, literally in communication with one another, cannot have emerged "out of nothing" by chance, nor have been assembled by means of a chain of unconscious events and begun their functions, again by chance. Anyone of reason and good conscience, who reflects honestly and is not unmoved by what he sees and knows, will immediately appreciate this obvious fact. The boundless nature of the blessings imparted by Allah is revealed in a verse:
Is He Who creates like him who does not create? So will you not pay heed? If you tried to number Allah's blessings, you could never count them. Allah is Ever-Forgiving, Most Merciful. (Surat an-Nahl: 17-18)
Even more striking details are contained within the stomach's digestive processes. The stomach is lined with a perfect protective material. The sensitive goblet cells secrete this protective mucus, which works just like a protective layer, even before the acid and breaking-down enzymes are emitted. Despite this protective substance's extraordinary strength, the stomach still loses 1.5 million cells a day to the effects of acid and enzymes. The entire internal lining of the stomach is destroyed, but then renewed, every three days.
The stomach might not have always renewed these naturally dying cells. This system is so tightly controlled that you are totally unaware of its ongoing intervention. New cells are always produced to replace those that die. Both the destruction of old cells and the production of new ones take place at Allah's choosing.
Ulcers are a reminder of the consequences of the absence of such a system. The disorder involves a failure to secrete protective mucus for one reason or another. Acid and enzymes begin damaging the stomach wall and blood begins leaking from the blood vessels beneath. The stomach wall now has an open sore. Until treated, the stomach's own secretions will continue to kill the stomach cells, and foodstuffs will not be digested.
Following the release of protective mucus in the stomach, food reaches the upper portion of the stomach for digestion. No enzymes are secreted here. Raw food goes into this section of the stomach. After swallowing, digestion continues here with these food's own enzymes for half an hour to an hour. After that, pepsin, the stomach enzyme, takes over.
If the food has been cooked, it waits in this section of the stomach for half an hour to an hour, with no enzymes breaking it down. Salivary enzyme breaks down carbohydrates, but protein and fat have to wait. These foods are subjected to a different process in the stomach than raw foods which already contain enzymes, because the body's metabolism must devote its attention to supplying more metabolic enzymes for the organs and tissues. In other words, another conscious choice is made inside the body. After being kept in this stomach region for a while, the food will start being broken down by gastric enzymes.59
The process of acid secretion in the stomach is controlled by the presence of food. In response to food's presence in the stomach, specific cells go into action, secreting a hormone known as gastrin into the bloodstream. It then emits a signal to the glands that secrete hydrochloric acid and thus stimulates secretion of gastric juice.
The nervous system also has a role in the secretion of gastric juice, because the glands responsible are under the control of the nervous system. So, the release of digestive fluids is controlled by both hormones and by the nervous system, which is why increased stress and high blood pressure may lead to the formation of ulcers. Indeed, that it is enough that we smell, taste or even think of food for the brain to send messages to the secretory glands in the stomach demonstrates the efficiency of the nervous system in the digestive process.60
Pepsin is the active enzyme that breaks down proteins in the stomach. The stomach wall cells produce this enzyme in an inactive form, known as pepsinogen. As already mentioned, hydrochloric acid converts pepsinogen into pepsin. The secretion of pepsinogen by the gastric secretory glands is at the same time controlled by the activities of the hormone gastrin. The presence of food in the stomach, the secretion of gastrin, the production of hydrochloric acid and the conversion of pepsinogen into pepsin are all interconnected. Therefore, the entry of food into the stomach initiates a chain of highly complex stages.
Pepsin converts large protein molecules into small polypeptides, but each polypeptide molecule contains a large number of interconnected amino acids. The breaking down of these continues in the small intestine.61
There is a gate where the stomach opens into the intestine, whose presence is of great importance, because if the stomach were not separated from the intestine, it would entail the possibility of foods in the intestine being returned to the stomach, which would have a damaging impact on the stomach's own acidic environment. Enzymes in the intestine operate in a more neutral and alkaline environment, and these special enzymes would be impaired by the stomach's acidity and give rise to dangerous consequences.62
Digestive enzymes have similar structures and functions, yet those that function in the intestine cannot adapt to the gastric environment, nor vice versa. This shows that every region, every tissue and every organ in the body is created with different properties; and that enzymes have also been equipped with features appropriate to the conditions in these separate environments.
Special Enzymes in the Intestine
The intestine has been specially created for the breaking down of foodstuffs. The chemical events that take place in the walls—and the flawless system involved in breaking foodstuffs down into their smallest components and their subsequent distribution—are truly amazing. Just about every square millimeter of the intestinal wall produces countless enzymes that separate proteins into different peptides and break these down into amino acids, carbohydrates into glucose and fats into fatty acids and glycerol. These enzymes are of very different kinds, with different functions and work at different speeds. An enzyme that breaks down fruit sugar, or fructose, is very different from one that breaks down sugar in dairy products, or lactose, and yet another enzyme breaks down starch. Because, as we have already seen, enzymes have very sensitive working conditions, the temperature and pH here are maintained at the ideal levels for these enzymes to be manufactured and perform their separate functions.
Since the structure and mode of operation of the stomach and the intestine are completely different, enzymes able to function in an acidic environment must be present in the stomach, while ones able to work in an alkaline one in the intestines. Foods leaving the harsh conditions of the stomach encounter gentler ones in the small intestine. The partly digested food and gastric juices passing from the stomach must do no harm to the intestine. This is where the pancreatic juice comes into play.
As you shall shortly see in some detail, pancreatic juice and its special enzymes enter the duodenum by way of the pancreatic duct and make the pH level more alkaline. In the duodenum, enzymes enable fats to be broken down. The fat-dissolvers manufactured in the pancreas accelerate the digestion of foods by accumulating here. Pancreatic juice contains trypsin, a particularly powerful enzyme, which enters the duodenum in an inactive form, trypsinogen. This is activated by an intestinal enzyme which is triggered solely in the presence of food, and turns into trypsin, which breaks down the peptide bonds of polypeptides into smaller peptide fragments. Trypsin also breaks down large protein molecules that have not been affected by the pepsin in the stomach.
Secretory glands in the duodenum walls also release other enzymes that separate peptide bonds. The bonds that form molecules are torn apart and the final products that emerge as the result of protein digestion are amino acids, the fundamental building blocks of all proteins.
Fats ingested with food are also digested in the small intestine. However, they arrive in the form of small fat droplets. The enzyme lipase involved in fat digestion cannot act on fats when they remain in that state. This is where bile juice enters the equation. Bile is secreted by the liver and stored in the gall bladder, and contains no digestive enzymes. Bile salt present in the bile juice breaks down fats into smaller globules and prepare them to be digested by the enzyme lipase. Up to 90% of bile salt is absorbed as it passes through the lower region of the small intestine, and is then routed back to the liver to be used again for digestion.
Once the bile juice has done its job, fat-digesting enzymes then have their turn. The enzyme lipase in the pancreatic juice acts on fats and converts them into fatty acids and glycerol.
Throughout this process, hundreds of precautionary steps are taken. Foods arriving from the stomach must not carry the stomach's acidity with them into the small intestine. Specific enzymes for digesting still-undigested foodstuffs also need to be present; and the environment needs to be regulated so as to make all this possible. Chemical messengers need to act accordingly, and helper molecules need to be on hand. It is the pancreas, a very special organ, that secretes the particular juice for all of these tasks.
The Pancreas: The Factory That Produces Digestive Enzymes
The pancreas is a small organ, six inches in size and three ounces in weight. It is named the body's "hidden organ" because of its location concealed behind the stomach. It contains fine, interconnected tubes or vessels that come together in the form of a doorway opening into the duodenum, where pancreatic juice passes through, to play a life-saving role for the intestine.
Despite its small size, the pancreas performs a very important function in secreting digestive enzymes, which are transported to the digestive system in what is known as pancreatic juice. There are other moderating factors in this fluid, of which the pancreas produces up to 5 liters a day63—very high level of production for a organ weighing just 3 ounces.
The production of pancreatic juice is triggered when the duodenum encounters gastric juice. After leaving the stomach, foodstuffs have assumed a rather pulpy consistency and they first arrive at the duodenum. This mixture arriving from the stomach is powerfully acidic enough to dissolve the thin, delicate interior of the duodenum. Yet this does not happen, because pancreatic juice is alkaline, neutralizing the acidity in question. Foodstuffs are thus able to pass into the small intestine without endangering it...
The production of pancreatic juice is a controlled process. When you sit down at the dinner table, thousands of tiny saclike cavities, or acini, in the pancreas receive stimuli from the nervous system and begin producing pancreatic juice. However, the pancreas does not start working at full capacity until your food actually passes through the duodenum doorway. The more food arrives, the more enzyme that is secreted.
The pancreas can also distinguish between the kinds of food we consume, and secretes different enzymes accordingly. For example, when you eat foods such as pasta or bread that are rich in carbohydrates, the pancreas secretes mainly a carbohydrate-digesting enzyme called amylase.64
This mechanism is exceedingly sensitive, because enzymes must not be wasted, and at the same time, the intestine must not accidentally digest its own walls. This entire system must produce adequate enzymes to keep a living body alive. Were this process under our conscious control, we would spend all our time calculating when, which, and how many enzymes needed to be produced and pondering about to make use of them. However, their production and operation are actually beyond our control and knowledge. Other structures—again consisting of fat and proteins—are charged with controlling enzyme production. Hormones specially manufactured in the intestinal wall, secretin and pancreozymin, take on the job of stimulating enzyme production. The hormone secretin stimulates the pancreas into secreting pancreatic juice, rich in the sodium bicarbonate that neutralizes acid. The hormone pancreozymin stimulates the production of enzymes by the pancreas.
When food passes from the stomach to the duodenum, secretin and pancreozymin are released into the bloodstream. Thanks to these hormones, the duodenum is protected from the destructive effects of hydrochloric acid. By way of the bloodstream, secretin and pancreozymin reach the pancreas and signal it to produce sufficient quantities of fluid rich in water, bicarbonate and digestive enzymes, which will protect the duodenum. These secretions, as already mentioned, reach the duodenum through the pancreatic duct.
The organ that sets the hormones in motion is the stomach—another organ consisting of fats and proteins. As its digestion continues, the stomach sends a message to the duodenum, as if it knew that the potentially dangerous foodstuffs are headed there next. It immediately begins secreting the needed hormones in question and releasing them into the bloodstream. At first glance, this would seem to be a risky business, because the blood travels through the entire body. Therefore, these hormones need to know where they must carry their signal. But in fact, they transmit their message to the pancreas alone, without stopping off at any other cells. As evidence of the infinite detail within His creative artistry, Allah has created the molecular structure of these hormones to interact only with receptor molecules on the membrane of the pancreatic cells.
Two small molecules, quite unaware of one another's existence in the human body, communicate with each other, knowing what purpose they serve, their objectives, properties and duties. They never see one another, and have no idea what the human anatomy looks like or how large it may be. They need to have great intelligence and consciousness in order to communicate this way, to achieve a common objective. Of course, there is no point in looking for intelligence and consciousness in molecules with no eyes, ears or brain. The intelligence and consciousness apparent in the miraculous tasks performed by these substances belong to Allah, Who created the human body from nothing. One of the reasons in creating this miraculous detail is for people to perceive and reflect on this great truth, reported in these terms in the Qur'an:
It is Allah Who created the seven heavens and of the earth the same number, the Command descending down through all of them, so that you might know that Allah has power over all things and that Allah encompasses all things in His knowledge. (Surat at-Talaq: 12)
The pancreas's ability to manufacture enzymes according to the nature and quantity of incoming foodstuffs is another miracle all its own. The pancreas must know chemical formulae, establish what enzymes will digest which kinds of food, and engage in production accordingly. As a result of this controlled process, the pancreas sends to the duodenum its enzyme-rich fluid, containing four enzymes of vital importance to the body: trypsin, chymotrypsin, lipase and amylase. The first two, trypsin and chymotrypsin, break down protein into amino acids that later travel the whole body through the bloodstream and are used in tissue manufacture. Amylase converts starch into simple sugars. Lipase breaks down fat droplets, converting them into fatty acids and glycerol. Thanks to enzymes' enormous speed, this is all completed in a very short time. Whether you consume a special meal ordered from a four-star restaurant or just a simple slice of bread, it all assumes the same appearance in the duodenum. The state of the food on your plate is completely different from how it winds up in the duodenum. Enzymes break it down, reduce its particles in size, eliminate wastes and separate the rest for the purpose of keeping your body alive.
Digestive Enzymes and Their Perfect Organization
When synthesized in the pancreatic cells, some enzymes are not yet in an active state. These become active only after passing through the intestinal tract. The chemical trypsin, one of the enzymes already mentioned, represents a potential danger to the body's cells. For that reason, it is secreted in an inactive form known as trypsinogen. The moment trypsinogen makes contact with the intestinal mucosa, the enzyme enterokinase secreted by the mucosa converts it into its active state. Trypsinogen is also activated by the trypsin that already exists.
It is most important that these enzymes in pancreatic juice should not be active before they progress to the intestine, or else trypsin and other enzymes might digest the pancreas itself. Thus the cells that secrete the enzymes in question also release a substance known as a trypsin inhibitor, which prevents trypsin from going into action inside the cells that secrete it and in the pancreatic duct. Since trypsin can activate other enzymes, the trypsin inhibitor thus also prevents their activation.
These two enzymes—trypsin and its inhibitor—have no effect when secreted together. But once they reach the duodenum, they separate from one another just as if they had been ordered to do so. This division is very important to the digestive process, since the trypsin, suddenly released, starts breaking down proteins in the food reaching the duodenum. The moment and site these two substances separate is very exact. Were they to part company too early, trypsin would break down the pancreas itself. If they never separated, then food entering the body would not get digested. Yet they never fall into such errors. Every meal you consume is digested as a result of these two molecules knowing just when to separate from one another. This happens in exactly the right place and at exactly the right time.
It is of course impossible for enzymes to be able to establish such timing by chance or under their own volition. An enzyme, another protein that inhibits it, the pancreas that manufactures them, the hormones that travel between them as messengers—plus all the molecules, other proteins and enzymes involved in these phenomena—cannot all be in the same place at the same time or act together in complete harmony by chance. It is impossible for even a single one of these to have formed by coincidence. Allah creates them all, and they are all in a constant state of obedience to Him.
What would happen if there were no trypsin inhibitor? Any failure of this mechanism to function could result in death. For example, when the pancreas suffers severe injury, or when a passage is blocked, a large amount of pancreatic secretions accumulates in the damaged area. That might make the trypsin inhibitor being insufficient to keep the enzymes, working together at very high speed, from digesting the whole pancreas in a matter of a few hours. The result would be shock, usually ending in death, or a lifetime of pancreatic deficiency.65
If the pancreas can't secrete enough fluid to ensure digestion, this of course presents a major problem. However, the body has taken a precautionary measure against this. In such an eventuality, the pancreas sends messages everywhere in the body in order to locate metabolic enzymes which, when it receives them from other regions of the body, it can convert into digestive enzymes. For the pancreas, this task is very different and more difficult, and since it must work harder, it enlarges. This enlargement does the pancreas no harm, though it does cause pain to the body, and the use of the body's metabolic enzymes for digestive purposes does mean a reduction in the functions of other organs. Dr. Edward Howell explains:
Michael Behe is a professor of biochemistry at Lehigh University. In his book Darwin's Black Box, he described in full detail the complexity involved in the blood-clotting process and the systematic way that enzymes function, pointing to the complex and interconnected details in the clotting system as evidence of what he announced as "irreducible complexity." In the following passage, Behe describes another example of the human body's irreducible complexity: the importance of the pancreatic enzymes, one of the most valuable components of the digestive system:
Pancreatic enzymes, which have to digest a wide variety of protein foodstuffs, are among the most nonspecific of enzymes. Now, that would pose a severe health threat to the organism even greater than just an unregulated clotting cascade. For example, if the digestive enzyme precursor trypsinogen were mistargeted to the bloodstream, the potential for disaster would be very large. In the pancreas, misactivation of trypsinogen is prevented by the presence of trypsin inhibitor. In Miller's scenario one cannot plausibly suppose there to be a trypsin inhibitor fortuitously circulating in the plasma. If the mistargeted enzyme were accidentally activated, it would most likely cause generalized damage in the absence of a regulatory mechanism. It would not be a viable evolutionary intermediate. 67
Such a miraculous system, in which no error ever occurs and which functions so perfectly with its enzymes and the organs that manufacture them, is a blessing to constantly remind us of the existence of Almighty Allah. These reminders tell us that humans were not brought into being for no reason and that once they die, they will inevitably be confronted with the life of the Hereafter. If people have the wisdom and understanding necessary to draw conclusions from all this, then all the enzymes and other structures in their bodies will become means whereby they take a step closer to the mercy of Allah, and thus to Paradise. Allah has created all His works toward that end, and every miracle of creation will be a means whereby the person who understands it will attain the true path to the beauties in the Hereafter. People are tested in this way, as Allah tells us in the Qur'an:
We created man from a mingled drop to test him, and We made him hearing and seeing. We guided him on the Way, whether he is thankful or unthankful. (Surat al-Insan: 2-3)
Enzymes That Work for DNA
Enzymes are very special proteins that unfailingly identify which reaction they need to act on and where; and seemingly know how much they need to accelerate it. But perhaps the most interesting of all the enzymes that work in the body are those that work for DNA—and which also represent a major predicament for the proponents of the theory of evolution. Because these enzymes' existence totally does away with the theory's claims regarding chance, as we shall see in due course.
One of the most interesting aspects of DNA enzymes is that they receive all their operational knowledge from DNA, but can also determine and repair any errors in that same DNA. As we know, the DNA molecule is capable of copying itself, but it does not perform this replication process on its own. Enzymes also become involved. The replication takes place, at Allah's choosing, by way of enzymes.
DNA is a giant molecule consisting of a data bank of 3 billion "letters." This molecule resembles a spiral staircase twisted into a helix shape. When replication first begins, the enzyme known as DNA helicase separates the two DNA strands like a zipper, at a rate of up to 1,000 nucleotide pairs a second.
As it opens the zipper, DNA helicase suddenly stops at the points that represent the limits of the information required. (When a process is to be carried out in the cell, only that part of the DNA code concerning that process is copied.) The enzymes know how far the information extends and how far the DNA helix needs to be pried apart.
In principle, the unwinding of the DNA helix is made possible by two DNA helicase enzymes acting together. One runs along the leading strand template, while the other runs along the lagging strand template. Since the two strands have opposite polarities, these helicases must move in opposite directions on the DNA strand, for which reason they are "different" enzymes. Both types of DNA helicase are present within the cell.68
Once the appropriate DNA region has been found, other enzymes that attach to that region begin reading the nucleotides three by three. The reason for this is that the information is encoded in triple nucleotide strings. (Nucleotides are the constituent bases of the DNA nucleic acid and are known by the names of adenine, thymine, guanine and cytosine.) Millions of nucleotides all joined to one another are constantly read by the enzymes, and this whole process takes less than a second.
However, the enzymes that will read and copy the four kinds of nucleotides in DNA—adenine, thymine, guanine and cytosine—are made up of amino acids. Therefore, how an enzyme communicates with the DNA helix, and how the nucleotides and amino acids understand one another, is something truly extraordinary, since we are looking at two totally different structures. There is no molecular similarity here to permit a lock-and-key type of compatibility. In molecular terms, therefore, it would seem very hard for them to establish a connection. However, a solution to this has also been created within the body. The enzymes are easily able to read the codons on the DNA and understand what these codons express. (A codon is a tri-nucleotide sequence of the code written from the DNA to the mRNA, or messenger RNA. Codons are found in the mRNA molecule.)
This can mean only one thing, of course—that the amino acids and nucleic acids were all created by a single Creator at exactly the same time. The way that the amino acids constituting the enzymes recognize the nucleotides, can resolve the codes they contain and use this to perform the vital function of DNA replication can only be explained by their all being under the control of a single Will. Like everything else that exists, they too are the works of Allah.
Leslie E. Orgel is one of the most dyed-in-the-wool modern evolutionists. Yet even he had to admit that these two structures could not have evolved by chance:
Following the unwinding of the DNA strands, other enzymes immediately flock to the DNA and begin scanning it. If during this scanning process, they detect any "error" in the DNA they immediately correct it. The faulty part of the damaged DNA strand is identified and torn out by an enzyme known as DNA nuclease. A gap thus appears in the DNA helix.
When the flawed section has been done away with, DNA polymerase enters the equation. This enzyme completes each of the two separated DNA strands with a second strand, so that two separate DNA helixes are formed. In stages it checks whether or not they match the bases on the other side. In order to do so, it brings in data corresponding to those data that comprise the original DNA strand. It separates flawed base molecules and replaces them with new ones. To put it another way, it copies 3 billion separate letters in a completely flawless manner. In addition, DNA polymerase checks all these different stages twice, never departing before the second checking process has been carried out. At the same time, another polymerase enzyme completes the other half of the DNA. As all this goes on, helix stabilizing enzymes cling on to the ends to prevent the two strands of the DNA helix from winding round one another again. Yet another enzyme intervenes in the renewed section to ensure that the correct, newly installed base is firmly in place.
The enzyme editase, which enters the scene in the wake of all these stages, again checks the separated part and checks the revisions that have been made. Once that has been performed, an identical copy of the original DNA is complete.
The correction process does not end here, however. You'll recall that there was a break in the DNA strand where the correction was performed. This break is repaired by the enzyme DNA ligase.
This repair is exceedingly important, since if any error occurs during such a vital process as DNA replication, the codons in the new nucleotide sequences will be disordered. With one missing nucleotide, all the codons read in triplicate will change, and as a result, molecules will be produced that mean nothing to the organism and the living body in question will start to die.
Another important enzyme works inside this extraordinary system during the synthesis of RNA from DNA. Instead of checking for incorrect and wrongly copied bases in RNA and extracting them one by one, this enzyme cuts base sequences out from the region like a pair of scissors, by identifying regions in which bases have been set out incorrectly. If this cutting process takes place in several regions simultaneously, instead of in one only, the DNA strand will begin to fall apart. To prevent this, the cell dispatches another enzyme to the region. This enzyme brings the divided DNA strands back together again and joins them up.70
Enzymes, with their enormous working capacity, result in perfect replication of DNA. This phenomenon is constantly taking place at great speed in every cell in the human body. Each and every day, in fact, some 20,000 repair processes are carried out in every one of the human body's 100 trillion cells.71
The enzymes that work to replicate DNA operate as quickly as permitted by the great care they take. In a striking way, enzymes working on DNA determine their speed according to the reactions they must perform. For example, DNA polymerase completes only some 10 or so bases a second. This rate is fairly slow, compared to enzymes such as catalase, which breaks down 5 million hydrogen peroxide molecules a second. This speed is determined by the quantity of copy DNA required by the body. The cell establishes its requirement, and the enzymes work in line with that production rate. At some places in the body, enzymes literally have to work approaching the speed of light, because where they operate, what counts is speed. The faster they complete their reactions, the better the body will be able to remain healthy.
Production of the enzymes that work for DNA is another controlled process. A large number of enzymes are involved in DNA replication, but their use and production are carried out economically. Again, the DNA itself controls this. An on/off switch on the DNA (repressor gene) keeps production under control. The switch is kept normally in an "off" position, until the need for an enzyme arises.72
Even a small electron exchange taking place in the body is important, and the results are very great. Every reaction must take place in a controlled manner. Every reaction requires a division of labor, and the involvement of countless enzymes all acting together. The duties and speed of each one, and the molecules they will act upon, must all be predetermined. Each enzyme must constantly strive to keep the cell healthy and never make a mistake. So who makes all these determinations? Who controls these and ensures that they are free of error? Who can program them in such a way as to keep such a complex mechanism as the human body alive and healthy? Who can maintain the interdependency in this giant system consisting entirely of tiny molecules?
It is Almighty Allah Who does and creates all this.
If a person can realize all this perfection in his own body and has the ability to comprehend it, then he will clearly see the existence of Almighty Allah, our Creator. It is He Who creates us, everything we have, and all entities on the Earth and heavens. Nothing is independent of Allah. Every living cell we examine is flawless because it acts under the direction of Allah. And because they are under His control, they demonstrate such abilities and extraordinary properties. It is a grave error and terrible ingratitude for anyone to ignore all this and imagine himself an independent entity, a miracle of coincidence, while in reality his entire being is in complete obedience to Allah. Even if some insist on ascribing this sublime creation to chance, every enzyme in their bodies, every protein and every electron exhibit harmony with the system determined for them by Allah and constantly take their inspiration from Him.
This fact is also imparted in verses from the Qur'an:
Everyone in the heavens and Earth belongs to Him. All are submissive to Him. It is He Who originated creation and then regenerates it. That is very easy for Him. His is the most exalted designation in the heavens and the earth. He is the Almighty, the All-Wise. (Surat ar-Rum: 26-27)
... everything in the heavens and Earth belongs to Him. Everything is obedient to Him. (Surat al-Baqara: 116)
Are Enzymes the Source of DNA, or the Other Way Around?
The question of DNA and enzymes working for DNA constitutes one of the greatest impasses confronting evolutionists. The "irreducible complexity" posing such a dilemma for evolutionists will be encountered again during the course of this section. DNA, one of the cell's most complex structures, and enzymes, some of the body's complex proteins, work together in a system in which neither can be separated from the other. It is impossible to remove even a single component from the complex system in which they participate and claim that some parts "evolved" before others.
As described in the previous section in some detail, DNA needs enzymes for the replication process. Yet at this stage, something very interesting arises. For the enzymes that enable DNA replication to come into being—which enzymes monitor the DNA at every stage, then correct any errors and check the DNA again from beginning to end—the necessary production information should already exist in DNA. Enzymes are proteins manufactured under DNA's control, according to the information encoded in that DNA. In other words, enzyme synthesis is impossible without DNA. On the other hand, in the absence of enzymes, the chemical reactions to produce the sugar ribose, the "backbone" of DNA and RNA, cannot take place. To put that another way, DNA synthesis in turn is impossible in the absence of enzymes.73 DNA is essential for enzymes to exist, and vice-versa.
This fact presents a severe disappointment to evolutionists. The precondition of the emergence of two complex systems is an even worse problem for the theory of evolution, which is unable to account for either one. Even if we accepted the impossible claim that DNA did emerge first, as the result of chance, we would also have to accept that it then waited for the development of those enzymes that would enable it to be copied—again by chance. Yet clearly, any DNA that had to wait so long to be replicated could be of no use to a living organism. Even if we believed another impossibility—that enzymes came into being, again by chance, before DNA, then we'd also be forced to accept that enzymes as yet had no data bank to store their production data and characteristics. Under these conditions, even if an enzyme did appear (despite all the impossibilities), it would still be impossible for any more to be produced. Therefore, the DNA-enzyme relationship constitutes an inseparable whole: The two have to co-exist together.
Evolutionists cannot offer any explanation as to what came into existence and how in our DNA-based life. These fundamental components display a truly irreducible complexity that must have existed ever since their beginning.
Charles McCombs, an organic chemist from California University, states that there can be no evolutionary history behind DNA and DNA enzymes:
It's of course out of question that two molecules might evolve together. Yet recall that evolutionists still can't explain the emergence of even a single DNA molecule or a single enzyme. Evolutionists will never be able to explain this because a chance emergence of an enzyme independently of DNA, or of DNA independently of enzymes, or even of a single enzyme or protein constituting DNA, is impossible.
The DNA-and-enzyme dilemma, which makes all claims regarding evolution totally irrelevant, is greeted with great astonishment by evolutionists. The American evolutionist biologist Frank B. Salisbury, whose articles appear in the American Biology Teacher magazine, admits the impossibility of any evolutionary explanation:
Despite his being an evolutionist, Caryl P. Haskins, director of the Washington Carnegie Institute, openly admits that it is impossible for these two interdependent complex systems to have evolved by chance:
But the most sweeping evolutionary questions at the level of biochemical genetics are still unanswered. How the genetic code first appeared and then evolved and, earlier than that, how life itself originated on earth remain for the future to resolve . . . The fact that in all organisms living today the processes both of replication of the DNA and of the effective translation of its code require highly precise enzymes and that, at the same time the molecular structures of those same enzymes are precisely specified by the DNA itself, poses a remarkable evolutionary mystery . . . Did the code and the means of translating it appear simultaneously in evolution? It seems almost incredible that any such coincidence could have occurred, given the extraordinary complexities of both sides and the requirement that they be coordinated accurately for survival. By a pre-Darwinian this puzzle would surely have been interpreted as the most powerful sort of evidence for special creation.77
Two complex structures are under discussion here. Evolutionists have not been able to explain the formation of enzymes, much less how the amino acids comprising an enzyme combined in the correct sequence to produce a protein. They have not even attempted to address the issue of DNA's origin. The fact that these two complex structures behave in such a way as to remind us of the question of the chicken and the egg—the way the one is responsible for the production of the other—represents a major difficulty placed at evolutionists' door by scientific progress.
This is actually one of the finest lessons that the science of microbiology can give evolutionists, who seek to offer an explanation other than creation for all the complex systems they encounter, and who propose exceedingly illogical and inconsistent claims on the subject. Evolutionists have no theory to suggest regarding the formation of both DNA and enzymes, nor any fictitious mechanisms to propose. They are dealing with an incomparable, astonishing and literally extraordinary miracle of creation. Clearly, both DNA and enzymes have been sited in just the right place in the cell for their separate functions and interdependent attributes. There can be no other explanation for this than creation.
Allah sees a single nucleotide in a DNA helix, a single atom it contains and every electron moving at a speed of thousands of miles a second, at every moment, and monitors and controls them all. Everything acquires a perfect complexity by Allah's choosing. Systems operate because that is Allah's will. Human beings remain alive because Allah so wishes. It is Allah Who knows every process taking place in every cell of every human being who has ever lived. It is Allah Who controls and creates out of nothing the thousands of processes taking place in the cell, the molecules involved in these processes and all the minute components that comprise them. That is why those who look for an explanation other than creation are constantly in a hopeless position. They themselves are also aware that they can offer no other explanation for all the things that Allah has created by commanding them to "Be!" Allah tells us of His boundless might in a verse:
The Originator of the heavens and Earth. When He decides on something, He just says to it, "Be!" and it is. (Surat al-Baqara: 117)
The Enzymes That Control RNA
RNA, or ribonucleic acid, is a large molecule that, like DNA, consists of consecutive nucleotides. However, different from DNA, it is single stranded and uses uracil instead of thymine present in DNA. By working together with DNA, RNA plays a role in the synthesis of enzymes.
For any process in our bodies—all the chemical reactions for the formation of a single growing hair, for example—the requisite enzymes have to be produced. Messages are therefore transmitted to that part of the DNA where enzymes are to be produced. Since DNA and RNA perform enzyme production together, RNA synthesis must also take place in that site where the message goes.
In order for that to happen, it's essential that the DNA should assume an active state, that the RNA should be exported from the nucleus into the cytoplasm, and that enzymes should be synthesized. Again, all the different stages in the synthesis of RNA are controlled by other enzymes. One of those manufactured, adenosine triphosphatase (or ATPase) establishes the use of ATPs, while another directs the ATPases to the proper location. Meanwhile, thousands of other enzymes carry out thousands of other reactions through similar stages in order to keep the cell alive. Yet one very important point needs to be emphasized: RNA is synthesized for enzyme production, yet it is enzymes that synthesize RNA!
RNA molecules brought into being by genes in the cell nucleus act as templates upon which enzymes are formed. If a living organism is born with a defective gene or if one of its genes is missing, that means the RNA molecule is incomplete, and that some enzymes have not formed in the cell. Therefore, those reactions dependent on the enzyme that's not been manufactured fail to occur, and the organism is defective. If the enzymes and reactions they perform are vital, the organism will inevitably die.78
Enzymes are manufactured by RNA, but RNA needs the enzymes themselves in order to be able to manufacture enzymes and correct errors in them. In other words, the same thing applies to RNA as applies to DNA; this system works just as with DNA. When a protein needs to be manufactured in the cell, an enzyme known as RNA polymerase travels to the DNA, the cell's data bank. It finds the data concerning the protein to be manufactured and makes a copy of them. Sometimes, however, the data regarding the protein to be produced may be dispersed in different regions. Under such circumstances, the RNA polymerase copies the entire region—from where the data begin to where they come to an end. In doing so, the enzyme also copies sequences that serve no immediate purpose.
The presence of unnecessary data will lead to the production of a different, useless protein. In order to prevent this, a new enzyme known as spliceosome enters the equation and removes the non-coding intervening sequences from among hundreds of thousands of pieces of data, then joins together the chains necessary for the manufacture of the protein.
At this point, the tRNA codon (transfer RNA: a small RNA chain that transports amino acids to the ribosome for protein synthesis) must be attached to the correct amino acid. There is at least one kind of tRNA for each of the 20 amino acids.79 If this vital stage in DNA replication does not function properly, then the DNA sequence will be damaged and be functionless.
A special enzyme, aminoacyl tRNA synthetase, is responsible for attaching the proper amino acid to the tRNA. During this process it has to be ensured that every tRNA carries the correct amino acid, and that none of the other 19 amino acids are affected. Since the enzyme in question works without error, these risks in the copying of DNA are totally eliminated.80
The dilemma in DNA replication also emerges in RNA replication. The proteins that permit RNA copying are, again, enzymes produced by RNA. It is therefore impossible to speak of enzymes in the absence of RNA, and vice-versa. Accordingly, evolutionists face insoluble problems regarding how RNA polymers can replicate in the absence of proteins.81
RNA's particular enzymes must be working at full capacity, and with all their functions, from the moment that RNA comes into being. Yet at the same time, those enzymes have to be manufactured by RNA. Evolutionists are unable to account for this contradiction, or to explain how even one of these structures might have come into being by chance.
Will they suggest that two basically different molecules that cannot operate independently of one another came into being accidently and for no reason, at exactly the same moment, and that they located one another and began working together—again by chance? Can any scientist who spent years training in laboratories and who knows this system down to the finest details make such a claim? To make such an unscientific, irrational claim solely in order to be able to deny the fact of Allah's creation would thoroughly discredit any such scientist.
For that reason, adherents of the theory of evolution are unwilling to advance such claims openly. Rather, they seek to disguise everything under a scientific mask, but also fail in that. The evolutionist Leslie E. Orgel is one of those who have had to admit this manifest impossibility:
We proposed that RNA might well have come first and established what is now called the RNA world... This scenario could have occurred, we noted, if prebiotic RNA had two properties not evident today: a capacity to replicate without the help of proteins and an ability to catalyze every step of protein synthesis.82
Here, Orgel is referring to an imaginary process such as evolution producing RNA, together with enzymes. In that fictitious process, however, it is impossible for even one of the components of these complex structures, let alone the structures themselves, to come into being by chance.
So perfect is Allah's creation that even if all the humans in the world joined forces, they still could not produce a single cell. They can propose no alternative explanation to Allah's creation. A system in which RNA cannot exist without enzymes, and enzymes cannot exist without RNA, is one of the indisputably finest examples of this perfection.
In the Qur'an, Allah tells us that He is the Creator of all things:
56 "Enzymes," http://www.juiceguy.com/Enzymes-how-to-get-more.shtml
57 Dr. Edward Howell, Enzyme Nutrition "The Food Enzyme Concept," Avery Publishing, 1985, p. 49
58 Ibid., p. 6
59 Ibid., p. 9
60 Martin Berg, Biology, Solomon, Villee, 3rd edition, p. 965
61 Biological Science "A Molecular Approach," BSCS Blue Version, 6th edition, D.C. Health Company, pp. 410-411
65 Arthur C. Guyton and John E. Hall, Tıbbi Fizyoloji (Medical Physiology), Nobel Tıp Kitabevleri, 1996, p. 824
66 Dr. Edward Howell, Enzyme Nutrition "The Food Enzyme Concept," Avery Publishing, 1985, p. 81
67 "In Defense of the Irreducibility of the Blood Clotting Cascade:
Response to Russell Doolittle, Ken Miller and Keith Robison," Michael J. Behe, July 31, 2000; http://www.arn.org/docs/behe/mb_indefenseofbloodclottingcascade.htm
68 Molecular Biology of the Cell, Alberts – Johnson – Lewis – Raff – Roberts - Walter, 4th edition, Garland Science, 2002, p. 245
69 Leslie E. Orgel, "The Origin of Life on the Earth," Scientific American, vol. 271 (October 1994), p. 78.
72 Dr Jean Lightner, "Special tools of life," 12 May 2004, http://www.answersingenesis.org/docs2004/0512tools.asp#n1
73 Rich Deem, "Is the Chemical Origin of Life (Abiogenesis) a Realistic Scenario?", www.godandscience.org/evolution/chemlife.html
74 Charles McCombs, Ph.D., "Evolution Hopes You Don't Know Chemistry: The Problem with Chirality," Impact; http://www.icr.org/article/105/
75 Frank B. Salisbury, American Biology Teacher, Sept. 1971, p. 338
76 Duane Gish, Ph.D., "Crack in the Neo-Darwinian Jericho Part II," Impact; http://www.icr.org/article/89/
77 Caryl P. Haskins, "Advances and Challenges in Science in 1970," American Scientist, vol. 59 (May/June 1971), p. 305.
79 Harper'ın Biyokimyası (Harper's Biochemistry), Robert K. Murray, Peter A. Mayes, Darly K. Granner, Victor W. Rodwell, Barış Kitabevi, 1993, p. 492
80 "The DNA - Enzyme System is Irreducibly Complex," http://www.ideacenter.org/contentmgr/showdetails.php/id/845
81 Rich Deem, "Origin of life: latest theories/problems," http://www.godandscience.org/evolution/rnamodel.html
82 Leslie E. Orgel, "The Origin of Life on the Earth," Scientific American, vol. 271, October 1994, p. 78.