What are enzymes?

Any living organism is a perfect system, in which literally every minute there are some chemical reactions. And these processes can not do without the participation of enzymes. So what are enzymes? What is their role in the life of the body? What do they consist of? What is the mechanism of their impact? Below you will find answers to all these questions.

What are enzymes?

Enzymes, or, as they are called, enzymes, are protein complexes. These are biologically active substances that act as catalysts for chemical reactions. In fact, the role of enzymes is difficult to overestimate, because without them there is not a single process in a living cell and the whole body.

The very term "enzyme" was proposed in the 17th century by the famous chemist Helmont. And although great scientists of the time understood that meat is digested with the presence of gastric juice, and starch under the influence of saliva breaks down to simple sugars, no one knew what exactly caused such processes. But already in the beginning of the 19th century Kirchhoff first isolated the saliva enzyme - amylase. A few years later, gastric pepsin was described. Since then, the science of enzymology has begun to develop actively.

What are enzymes? Properties and mechanism of action

First, it should be noted that all enzymes are either proteins in pure form, or protein complexes. To date, the amino acid sequence of most of the enzymes of the human body has been deciphered.

The main property of enzymes is high specificity. Each enzyme can catalyze only one type of reaction. For example, proteolytic enzymes can only break down the bonds between the amino acid residues of the protein molecule. Sometimes on one substratum (the object of the enzyme effect) can affect several enzymes that are similar in structure.

But the enzyme can be specific not only in relation to the reaction, but also in relation to the substrate. The most common group specificity of enzymes. This means that a certain enzyme can affect only a certain group of substrates that have a similar structure.

But sometimes there is a so-called absolute specificity. This means that the enzyme can bind to the active center of only one substrate. Of course, in nature this specificity is rare. But for example, we can recall the urease enzyme, which can catalyze only the hydrolysis of urea.

Now we have found out what enzymes are. But these substances can be completely different. Therefore, they are usually classified.

Classification of enzymes

Modern science knows more than two thousand enzymes, but this is by no means an exact number. For greater convenience, they are divided into six main groups, depending on the catalyzed reaction.

• Oxidoreductases are a group of enzymes that participate in oxidation-reduction reactions. As a rule, they act as either donors or acceptors of electrons and hydrogen ions. These enzymes are very important, as they participate in the processes of cellular metabolism and mitochondrial respiration.
• Transferases - enzymes that deal with the transfer of atomic groups from one substrate to another. Participate in the intermediate metabolism.
• Liazes - such enzymes are able to cleave from the substrate atomic groups without a hydrolytic reaction. As a rule, as a result of this process, a molecule of water or carbon dioxide is formed.
• Hydrolases are enzymes that catalyze the hydrolytic cleavage of a substrate using a water molecule.
• Isomerases - as the name suggests, these enzymes catalyze the transition of a substance from one isomeric form to another.
• Ligases are enzymes that catalyze synthetic reactions.

As you can see, enzymes are very important substances for the body, without which vital processes are simply impossible.