Any living organism - a perfect system where every minute there are any chemical reactions.These processes can not do without the involvement of enzymes.So what are enzymes?What is their role in the functioning of the body?What are they?What is the mechanism of their effects?Below are answers to all these questions.
What are enzymes?
enzymes, or as they are called, enzymes are protein complexes.This biologically active substances which act as catalysts of chemical reactions.In fact, it is difficult to overestimate the role of enzymes, because without them does not do any one process in a living cell and the entire organism.
The term "enzyme" was proposed in the 17th century by the famous chemist Helmont.Although the great scholars of the time understood that meat is digested in the presence of gastric juice, and starch by saliva breaks down into simple sugars, no one knew exactly what caused these processes.But in the early 19th century Kirchhoff first identified the enzyme salivary - amylase.A few years later he described gastric pepsin.Since then, the science of enzymology began to actively develop.
What are enzymes?Properties and mechanism of action
For a start it is worth noting that all enzymes are proteins either in pure form or protein complex.To date, the deduced amino acid sequence of the human body most enzymes.
main property of enzymes - a high specificity.Each enzyme may catalyze only one type of reaction.For example, proteolytic enzymes can only cleave linkages between amino acid residues of the protein molecule.Sometimes one substrate (the object of action of the enzyme) can affect several structurally similar enzymes.
but the enzyme can not only be specific to the reaction, but also in relation to the substrate.The most common group specificity of the enzyme.This means that a certain enzyme can affect only a certain group of substrates which have a similar structure.
but sometimes there are so-called absolute specificity.This means that the enzyme can bind to the active site of only one substrate.Of course, in the nature of this specificity is rare.But for example, we can recall the enzyme urease, which can only catalyze the hydrolysis of urea.
Now we have found that such enzymes.But these substances can be quite different.Therefore, to classify them.
Classification of enzymes
Modern science knows more than two thousand enzymes, but this is not the exact number.For greater convenience, they are divided into six groups according to the catalyzed reaction.
- Oxidoreductases - a group of enzymes that are involved in redox reactions.Usually, they act either donor or acceptor of electrons and hydrogen ions.These enzymes are important, as are involved in the processes of cellular metabolism and mitochondrial respiration.
- Transferases - enzymes that are involved in the transfer of atomic groups from one substrate to another.Involved in the intermediate metabolism.
- Lyases - such enzymes capable of cleaving the substrate atomic groups without hydrolytic reaction.Usually, by such a process forms a molecule of water or carbon dioxide.
- Hydrolases - it enzymes that catalyze the hydrolytic cleavage of the substrate by using a water molecule.
- Isomerases - as the name suggests, these enzymes catalyze the transfer of substances from one isomeric form to another.
- Ligases - enzymes that catalyze synthetic reactions.
As can be seen, enzymes - is a very important matter for the body, without which the processes of life are simply impossible.
