endopeptidázok

Endopeptidases are a class of enzymes that catalyze the hydrolysis of peptide bonds within a protein molecule. Unlike exopeptidases, which cleave amino acids from the ends of a polypeptide chain, endopeptidases act on internal peptide bonds. This action can lead to the fragmentation of larger proteins into smaller peptides or individual amino acids.

These enzymes are crucial for a wide variety of biological processes. In digestion, for example, endopeptidases secreted in the stomach and small intestine break down dietary proteins into smaller peptides that can be further processed by exopeptidases for absorption. In cellular metabolism, endopeptidases play roles in protein turnover, the activation or inactivation of proteins, and the processing of precursor proteins into their active forms.

The specificity of endopeptidases varies, with some cleaving at particular amino acid sequences, while others are less specific. Common examples of endopeptidases include trypsin, chymotrypsin, pepsin, and elastase, each having distinct cleavage preferences.

Endopeptidases are classified based on their catalytic mechanism. Major classes include serine proteases, cysteine proteases, aspartic proteases, and metalloproteases, distinguished by the amino acid residue or metal ion involved in the active site. Dysregulation of endopeptidase activity is implicated in various diseases, including cancer, inflammatory disorders, and neurodegenerative conditions, making them targets for therapeutic intervention.