Enzymes

Enzymes are molecules RNA or proteinaceous molecules, and also their complexes which are capable to lead to acceleration of chemical changes in a human body.

Substrates are reagents of reaction which accelerates enzymes, that is those substances which take part in reaction.

Products are the turned-out substances as a result of reaction.

Enzymes have a specificity to substata, that is certain enzymes can accelerate reactions in which certain substances take part.

Activators and inhibitors are substances which lead to increase or lowering respectively enzymatic activity.

Synonym of the term "enzyme" is the term "enzyme", and the science about enzymes received the name "enzymology".

Early studies of enzymes belong to the end of the 18th century when it was already known that digestion of meat in a stomach happens by means of a gastric juice, and starch becomes sugar under the influence of saliva. However the mechanism of such reactions was not known.

Functions of enzymes

Enzymes are present at any cells of a live organism, they promote transformations of one substance into another. Thus, enzymes are catalysts of a set of biochemical reactions which proceed in an organism. Enzymes have the major role in life activity processes, regulating and directing an organism metabolism.

As well as all other catalysts, enzymes can accelerate forward and back reaction, leading to decrease in activation energy of any process. At the same time there is no shift of chemical balance in any party. In comparison with proteinaceous catalysts distinctive feature of enzymes is their high specificity. Each molecule of enzyme can carry out to several million various "operations" in 1 second. Efficiency of enzymes considerably exceeds efficiency of nonprotein catalysts.

Enzymes divide into 6 classes according to on hierarchical classification which introduction was initiated by the International union of biochemistry and molecular biology. Each class of this classification has division into subclasses, in this regard enzyme registers in the form of four numbers which are divided by points. As a rule, enzymes are called as reaction which they catalyze, at the same time the suffix – an aza is added. Therefore, even different enzymes which carry out one function can be called equally. Such enzymes differ on other properties, for example, on localization in a cell or to optimum acid-base balance.

Many enzymes undergo modifications as a result of synthesis of a proteinaceous chain. Without such modification enzyme cannot show the activity fully. These modifications received the name "processing".

Many enzymes are capable to carry out the functions independently, without any additional components. But there are also enzymes for which additional components in the form of nonprotein breed are necessary. Inorganic molecules and organic can be them.

Between enzymes and hereditary diseases of a metabolism there is an interrelation. It was for the first time established in the 10th years of last century by A. Gerrod. The scientist still then called diseases which are connected with defects of enzymes, so-called "inborn errors of a metabolism".

When in any gene which codes a certain enzyme there is a mutation, there can be changes of amino-acid sequence. The majority of mutations as a result leads to the fact that catalytic activity strongly decreases, or in general vanishes completely. If the organism will receive on one such mutant gene from each parent, in an organism the reaction connected with this enzyme ceases to be catalyzed. Appearance of albinos , for example, is connected with the fact that tyrosinase enzyme which is responsible for one stage of synthesis of melanin stops being produced.

Today the set of hereditary diseases which are connected with defects of enzymes is studied. Still developments of methods of prevention and treatment of some such diseases continue.

Enzymes found wide practical use – in pharmacology, the food and textile industry, but is the widest, by itself, enzymes are applied in medicine and scientific researches.

Section: F