Any living organism is a perfect system in which literally every minute some kind of chemical reaction occurs . And these processes are not without enzymes. So what are enzymes? What is their role in the life of the body? What are they made of? What is the mechanism of their effect? Below are answers to all these questions.
What are enzymes?
Enzymes, or, as they are also 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 not a single process in a living cell and the whole body can do.
The term "enzyme" was proposed in the 17th century by the famous chemist Helmont. And although the great scientists of that time understood that meat is digested in the presence of gastric juice, and starch breaks down into simple sugars under the influence of saliva, no one knew what exactly caused such processes. But already at the beginning of the 19th century, Kirchhoff first isolated the salivary enzyme, amylase. A few years later, gastric pepsin was described. Since then, the science of enzymology began to develop rapidly.
What are enzymes? Properties and mechanism of action
To begin with, it is worth noting that all enzymes are either pure proteins or protein complexes. To date, the amino acid sequence of most enzymes in the human body has been deciphered.
The main property of enzymes is its high specificity. Each enzyme can catalyze only one type of reaction. For example, proteolytic enzymes can only cleave bonds between amino acid residues of a protein molecule. Sometimes a single substrate (the object of the enzyme) can be influenced by 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 the so-called absolute specificity. This means that the enzyme can bind to the active center of only one substrate. Of course, in nature such specificity is rare. But for example, we can recall the urease enzyme, which can catalyze only urea hydrolysis.
Now we have found out what enzymes are. But these substances can be completely different. Therefore, it is customary to classify them.
Enzyme classification
More than two thousand enzymes are known to modern science, but this is by no means their exact quantity. For greater convenience, they are divided into six main groups depending on the catalyzed reaction.
- Oxidoreductases are a group of enzymes that are involved in redox reactions. As a rule, they act either as donors or acceptors of electrons and hydrogen ions. These enzymes are very important because they are involved in the processes of cellular metabolism and mitochondrial respiration.
- Transferases are enzymes that transfer atomic groups from one substrate to another. Participate in the intermediate metabolism.
- Lyases - such enzymes are capable of cleaving atomic groups from the substrate without 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.
- Isomerase - as the name indicates, 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 substances that are very important for the body, without which vital processes are simply impossible.