karboksipeptidaz

Karboksipeptidaz is a type of enzyme that catalyzes the hydrolysis of peptide bonds at the carboxyl terminal end of a polypeptide chain. These enzymes are often referred to as carboxypeptidases or C-terminal exopeptidases. They play a crucial role in protein digestion and metabolism, as well as in protein processing and turnover.

Carboxypeptidases are classified based on their catalytic mechanism. For instance, serine carboxypeptidases utilize a serine residue in their active site, while metallocarboxypeptidases require a metal ion, typically zinc, for their activity. Another class, cysteine carboxypeptidases, employs a cysteine residue.

In mammals, digestive carboxypeptidases such as carboxypeptidase A and carboxypeptidase B are secreted by the pancreas into the small intestine. Carboxypeptidase A primarily cleaves aromatic and aliphatic amino acids from the C-terminus, while carboxypeptidase B specifically removes basic amino acids like arginine and lysine. This sequential action is vital for breaking down dietary proteins into absorbable amino acids.

Beyond digestion, intracellular carboxypeptidases are involved in various cellular processes. They can participate in protein maturation by removing signal peptides or pro-sequences, and in regulating protein levels through degradation pathways. Some carboxypeptidases are also implicated in wound healing and inflammation. Their precise substrate specificity and cellular localization determine their diverse biological functions.