Karboksüpeptidaases

Karboksüpeptidaases are a class of enzymes that catalyze the hydrolysis of peptide bonds at the carboxyl-terminal end of a protein or peptide. They are also known as carboxypeptidases. These enzymes are crucial for various biological processes, including protein degradation, processing of newly synthesized peptides, and digestion.

Carboxypeptidases are widely distributed in nature, found in bacteria, fungi, plants, and animals. In mammals, they play significant roles in the digestive system, breaking down dietary proteins into smaller peptides and amino acids for absorption. They are also involved in the post-translational modification of hormones and neuropeptides, generating their active forms.

The mechanism of action of carboxypeptidases involves the catalytic cleavage of the peptide bond adjacent to the C-terminal amino acid. This process releases the C-terminal amino acid or a short peptide fragment. The active site of these enzymes typically contains a zinc ion, which is essential for their catalytic activity in many cases, although some metallo-independent carboxypeptidases also exist.

Based on their substrate specificity and catalytic mechanisms, carboxypeptidases can be broadly classified into different types, such as carboxypeptidase A, which prefers hydrophobic or aromatic C-terminal amino acids, and carboxypeptidase B, which cleaves basic amino acids like lysine and arginine. Other subclasses exist with varying specificities. Dysfunctional carboxypeptidases can lead to various health issues, highlighting their importance in maintaining protein homeostasis and physiological function.