what are enzymes made of , Nature, mode of action and methods of enzyme production
Enzymes are molecules made up mainly of proteins that are found in every cell of every plant or animal. They are part of the energy centers of the cell – mitochondria, and start various chemical reactions or help the chemical reactions to proceed faster, without the enzymes themselves changing. Every civilization has used enzymes, whether it knew it or not, to make wine, cheese, bread. For millennia, enzymes have helped people prepare and preserve their food.
Enzymes are the ones that work constantly and keep us alive. At any given time in our body there are several million working enzymes that allow it to perform such complex tasks as breathing, reading, hearing, speaking. To date, more than 3,000 different enzymes have been found in the human body, millions of each of which maintain and renew our body and protect it from infections. Enzymes underlie the regulation of the set of chemical reactions, which is called metabolism. Metabolism can be conditionally divided into two groups of reactions – anabolism and catabolism.
- Anabolism is the process of building new compounds and structures (e.g., forming new tissue) by combining simpler starting compounds into more complex ones.
- Catabolism is the opposite of anabolism – it involves the processes that break down substances into simpler compounds (such as digestion). Enzymes catalyze the chemical processes that make metabolism possible.
Enzymes also play a role in substances that make food ingredients available for absorption by our body. The production of enzymes in our body can decrease after we reach adulthood, when we have injuries, when we are under stress and in that case their lack must be compensated by an external source. Deficiency of even just one enzyme would affect our entire metabolism and therefore we may need to eat enzyme-rich foods or special enzyme supplements.
Table of Contents
Basic classes of enzymes
Enzymes are classified into six main classes based on how they work, what their substrate is, and what type of reaction they start or accelerate. The six main enzyme classes are:
- Hydrolases – among other actions, this group of enzymes breaks down proteins, carbohydrates and fats in the digestive process by adding one molecule of water to their molecules.
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Isomerases – this group of enzymes acts as a catalyst for the rearrangement of certain chemical groups in the same target molecule.
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Ligases – by using an energy source, this group of enzymes acts as a catalyst for the formation of a chemical bond between two substrate molecules.
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Liases – by adding or replacing chemical groups, this group of enzymes acts as a catalyst for the formation of double bonds between atoms.
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Oxidoreductases – this group of enzymes makes possible the processes of oxidation and reduction.
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Transferases – this enzyme group transfers (transfers) chemical groups from one target molecule to another.
Most enzymes are “catabolic” – they break down complex compounds into simpler, digestible substances. For example, digestive enzymes help break down food into simpler compounds, such as amino acids, mono- and disaccharides, esters, and so on. by breaking the chemical bonds that support these simpler compounds into more complex molecules. All enzymes are substrate-specific, which means that, for example, one enzyme will be needed to break down proteins in meat and another – to break down the carbohydrates of potatoes.
How do enzymes work?
There are two main theories that try to explain the mechanism of action of enzymes:
Theory of key-lock interaction
According to this theory, the “right” substrate for an enzyme acts as a key that enters a specific active center of the enzyme – a “lock”, thus activating the enzyme.
Theory of inducible interaction
This theory assumes that once in the environment of its substrate, the enzyme changes its shape so that it can enclose the substrate or bind to it. As in other cases, it is now assumed that in real conditions both are true, ie the mechanism of action of enzymes is described by something in between these two theories.
The place where the enzyme binds to the substrate is called the active site. In order for an enzyme to exert its action on the target molecule – the substrate, it is necessary that the substrate has landed exactly in the active center of the enzyme. This is a type of precaution that aims at the enzyme recognizing only its specific target molecules, thus saving the cell energy. In order for a protein (enzyme) to catalyze a chemical reaction, the first prerequisite is that the enzyme and the substrate are already linked. Then, in the simplest case, if we denote the enzyme by E, the substrate by S and the product by P, then the main reaction pathway is: E + S -> ES -> EP -> E + P.
From this reaction pathway, it can be seen that there is a limit to the amount of substrate that a single enzyme molecule can process at a time. If the substrate concentration increases, the rate at which the product is formed also increases to one final, maximum possible value of Vmax. At this point, the enzyme molecule is saturated with the substrate, and the rate of the enzyme-catalyzed reaction depends only on how quickly the enzyme can process the substrate molecule. The maximum rate divided by the enzyme concentration gives the so-called. turnover number.
Usually the turnover is about 1,000 substrate molecules processed by one enzyme molecule per second, but there are also enzymes with turnover values from 1 to 10,000! Naturally, the working speed of enzymes depends on the “working environment” in which they are placed and is therefore influenced by the health of the individual.
Regulation of enzyme activity – enzyme cofactors, coenzymes and inhibitors
Most enzymes can only function if they are linked to small molecules called coenzymes or cofactors. Cofactors are some salts – zinc, magnesium, copper and calcium. In other cases, an inactive enzyme (called an apoenzyme) can only become active (a holoenzyme) if it binds to an organic (or unrestricted) compound called a coenzyme. Typical examples of coenzymes are vitamin C and B vitamins.
In addition to substances that are known to facilitate the work of enzymes, substances that suppress (inhibit) enzyme activity are also known. Some enzyme inhibitors are called “competitive” because they are structurally very similar to the enzyme-specific substrate and thus mimic it. As a result, the enzyme cannot distinguish between the substrate and its structural analogue (the inhibitor) and binds both types of molecules with equal probability, whereby the total rate of production of the target product P decreases.
It is obvious that the higher the concentration of the inhibitor and the lower the concentration of the substrate, the stronger the decrease in enzyme activity. Other enzyme inhibitors are called “non-competitive” because they reduce the rate of production of the final product regardless of the substrate concentration by reacting with reactive centers in the enzyme molecule, other than the active centers – allosteric control centers.
Most drugs act as allosteric inhibitors. The same applies to organic solvents such as methanol, ethanol, ethylene glycol and others, which also inhibit the functioning of a wide range of enzymes. However, sooner or later each enzyme “gets tired” of work and then “dies” – it breaks down. Once an enzyme begins to show signs of “fatigue,” other enzymes break it down and transport the waste products for re-entry into cellular anabolism.
Some enzymes only last for about 20 minutes, while others last for weeks. In place of the removed, functionally unfit enzyme, comes a newly synthesized enzyme of the same type.
How are enzymes produced?
Our bodies produce a number of enzymes that are the same as those of many different animals. For example, trypsin (produced by the pancreas in humans) is also found in many other organisms, such as fish and insects. Regardless of its origin, trypsin is a hydrolase and will always catalyze the same reaction, and therefore we know what action to expect from enzymes that have been isolated from animals.
The most common animal organs from which enzymes are derived are the pancreas, liver and / or stomach of pigs, cattle and other cattle. The enzymes that are extracted from these organs are a wide range of proteases, amylases and lipases such as trypsin, chymotrypsin, pepsin and renin. Other forms of the enzyme supplement are protomorphogens. These include supplements produced by organs or glands that contain the naturally occurring enzyme set of the organ / gland concerned. Such supplements can be obtained from the pancreas, thyroid gland, ovaries, testicles, brain and others.
Because they are in their natural proportions, the amount of enzymes in the composition of protomorphogens depends on the type of animal, organ or gland from which they are isolated and the method of processing. Apart from animals, many enzymes can be derived from some plants with particularly high amounts of enzymes. These are the enzymes found in pineapple (bromelain), papaya (papain), fig (ficin) and barley (malt diastase) – they can be obtained directly from food by consuming it directly.
Bromelain, for example, helps digest protein to amino acids, so you can safely eat dried pineapple with a protein shake. In addition, the high content of vitamins and minerals makes pineapple one of the most complete, enzyme-rich foods. Bacteria and some microfungi are another source of enzymes known as microbial enzymes. To be produced, microorganisms are cultured in a special nutrient medium in medium-sized vessels called bioreactors.
Due to the different types of fermentation that the microorganisms carry out in the bioreactor, the accumulation of enzymes in the nutrient medium or inside the cells themselves is observed. Relatively cheap and highly efficient enzymes are obtained by special methods of separation, isolation and purification from the microbial biomass or from the culture medium. For this reason, the biotechnological production of enzymes gives about 90% of all industrially produced enzymes. A similar technology is used in the production of vitamins, amino acids and antibiotics. Some of the enzyms that are included in the composition of enzyme-containing supplements will be discussed in another article.
