carboxypeptidaser

Carboxypeptidaser is not a widely recognized term in biochemistry. It is likely a misspelling or variant of carboxypeptidase, a family of enzymes that catalyze the removal of amino acids from the C-terminus of peptides and proteins.

Carboxypeptidases are exopeptidases, meaning they act on the ends of polypeptide chains rather than internal peptide bonds. Most enzymes in this family are zinc-dependent metalloproteases. Their catalytic mechanism centers on a bound zinc ion that facilitates nucleophilic attack by a coordinated water molecule, leading to hydrolysis of the terminal peptide bond and release of a single amino acid. A conserved active-site motif, commonly HEXXH, coordinates the metal and participates in catalysis.

Substrate preferences vary among members. Pancreatic carboxypeptidase A and carboxypeptidase B, for example, differ in their C-terminal amino-acid specificities: A favors bulky hydrophobic residues, while B favors basic residues such as lysine and arginine. In addition to these secreted enzymes, cells contain cytosolic carboxypeptidases (for example CCP1–CCP6) that participate in peptide maturation, signaling, and metabolic pathways rather than digestion.

Physiological roles include the terminal processing of dietary proteins, maturation and inactivation of peptide hormones and neuropeptides, and protein quality control. In research and industry, carboxypeptidases are used to modify peptides, study proteolytic pathways, and in certain biotechnological applications for precise C-terminal trimming.

Defects or inhibition of carboxypeptidases can affect digestion and peptide regulation. Clinically, pancreatic carboxypeptidase activity is often assessed in the context of digestive health and enzymatic function.