Protease

Protease (from ancient Greek πρωτεῖος - primary + άω - decompose) is an enzyme that catalyzes the hydrolysis of peptide bonds in proteins, peptides and other biopolymers. Proteases are also called peptide hydrolases or proteinases.

Proteases play an important role in many biological processes, such as food digestion, protein activation and inactivation, regulation of cellular processes, and apoptosis. They are involved in diseases such as cancer, inflammation, infections.

Proteases are classified according to their catalytic mechanism, active site structure, optimal pH, and substrate specificity. The main classes of proteases: serine, cysteine, aspartate, metalloproteinases, etc.

Protease inhibitors are used as drugs, for example to treat HIV, hepatitis C, hypertension, and inflammatory diseases. Proteases are also used in industry, for example in the production of detergents and in the food industry.

Proteases (proteolytic enzymes) are specific proteins that cleave peptide bonds between amino acids in a polypeptide chain to form amino acids:

+ for three- and more low-molecular polypeptides (di-, tri-, tetra-, oligopeptides); + individual amino acids; + oligosaccharide units of the peptide (for example, di- or polysaccharides).

They are divided into pyridine-dependent enzymes (endopeptidases), whose action is mediated by calcium phosphate ester Ca2+, and pyridine-independent enzymes (exopeptidases). The latter, upon hydrolysis of the peptide bond, do not release free octane amino cation and exhibit a wide spectrum of action. Due to this, they are a hydrolase system for the destruction of protein complexes. In contrast, the first methods hydrolyze peptide bonds and use the formed free octane cation. Endoproteinases, in turn, can be divided according to their action into nucleases (DNAases) and metalloproteinases (they are distinguished by the free metal Ca+).

Exo- and endoproteinases are divided into classes according to their mechanism of action: type:

+ Neutral - do not require cofactors. They are called independent proteases without secreting a cofactor. + Activators - proteins. The action is activated by the binding and cleavage of asparine (or other monomers), requiring myonecrotoc and about 6 Na+ ions to initiate the catalytic cycle. Among them are: alkaline and acidic. + Metalloproteases - combine the positive properties of the first and second and require a complex of metal ions and acid for their activity. Among them, a distinction is made between zinc-dependent and silver-dependent, which are also included in the class of metal-activated ones. Activity also depends on Ca+. The main group of Zn2+-dependent metalloproteases is represented by serine, thiol, cysteine ​​and aspartic endopeptidases. In addition, they possess amidase and lysyl oxidase. Cysteine ​​acids ensure the production of active forms of serotonin. Thiols destroy blood and immunoglobulin and complement complexes, asparin has caspase, which provides an antimicrobial effect.

The most basic group of enzymatic endopeptides has secretory activity - exocrine pancreatic proteases, which participate in digestion and are the most widely used. Next come trypsin, chymotrypsin and elastase - the main participants in the proteolysis of proteins and glycoproteins. Intestinal proteinase is the weakest exoprotease.