Hydrolases

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Hydrolases

 

a class of enzymes that catalyze reactions of hydrolytic decomposition (with the participation of water) of intramolecular bonds (hydrolysis). Hydrolases are widespread in plant and animal cells. They participate in processes of metabolism of proteins, nucleic acids, carbohydrates, lipids, and other biologically important substances. Depending on the type of bond hydrolyzed, hydrolases are divided into a number of subclasses: hydrolases acting on ester bonds (for example, lipase), glucoside bonds (amylase), peptide bonds (pepsin), and acid-anhydride bonds (adenosine triphosphatase).

By their chemical nature, most hydrolases are simple proteins. The presence of unaltered sulfhydryl groups (SH—) with a definite place in the polypeptide chain is necessary for the appearance of their catalytic activity. A number of hydrolases are produced in crystalline form (urease, pepsin, trypsin, and chymotrypsin). The mechanism of the catalytic action of some hydrolases that have been studied includes the addition of an enzyme, with decomposition of the substance followed by splitting off of the reaction products and liberation of the enzyme. It has been shown that in the mechanisms of enzymatic hydrolysis there is much in common with the action mechanism of transferase and that some hydrolases can transfer the groups being split off not only to water but also to other molecules.

E. I. KOROLEV

References in periodicals archive ?
Microorganisms are the best and cheaper source of starch hydrolyzing enzymes (Kaur et al.
It is concluded that the seed germination is noticeably reduced by Cd toxicity due to reduced activities of key hydrolyzing enzymes a-amylase and protease.
A welcoming reception will be held on the evening of Sunday, March 5, with the event officially opening the following morning with a group of sessions focused on fuel alcohols from grains and sugar, including a plenary lecture on "State-of-the-art Production of Fuel Ethanol Using Granular Starch Hydrolyzing Enzymes.
The first product from its line of STARGEN[TM] granular starch hydrolyzing enzymes was recently introduced.
Laboratory experiments indicate a well documented isolation, identification and purification of extra-cellular cuticle hydrolyzing enzymes from entomopathogenic fungi and their induction in cultures containing cuticle as substrates has been studied [4].
The genera Neocallimastix, Orpinomyces and Piromyces are members of Family Neocallimastigaceae and they are very close in genetic relation and the genes encoding glucose hydrolyzing enzymes are highly homologous among anaerobic fungi (Harhangi et al.
It was much later in 1930 that Ohlsson suggested the classification of starch hydrolyzing enzymes as a and ss-amylases according to the anomeric type of sugars produced by the enzyme reaction (Gupta et al.