Carboxypeptidase B

Carboxypeptidase B is an enzyme that plays a crucial role in the protein digestion process. It is a member of the metalloprotease family, which are enzymes that require a metal ion to function properly. Specifically, carboxypeptidase B is a zinc-dependent enzyme. This enzyme is primarily involved in the hydrolysis of the basic amino acids lysine and arginine from the C-terminal (carboxy-terminal end) of peptides and proteins. This action is essential for the breakdown of dietary proteins into their constituent amino acids, which are then available for use in various biological processes within the body.

Function

Carboxypeptidase B is synthesized in the pancreas as a zymogen, procarboxypeptidase B, and then secreted into the small intestine where it is activated. The activation process involves the removal of a propeptide segment from the zymogen, a step that is facilitated by another enzyme, trypsin. Once activated, carboxypeptidase B exerts its effect by cleaving amino acids from the carboxy-terminal end of proteins and peptides. This specificity for basic amino acids, such as lysine and arginine, distinguishes it from other carboxypeptidases, such as carboxypeptidase A, which preferentially cleaves hydrophobic amino acids.

Clinical Significance

Carboxypeptidase B has been studied for its potential therapeutic applications. Its ability to cleave basic amino acids is utilized in certain clinical settings, such as in the preparation of insulin for diabetic patients. Additionally, abnormalities in the enzyme's function or its inhibitors can lead to various diseases and conditions, making it a target for medical research.

Biotechnological Applications

In the field of biotechnology, carboxypeptidase B is used for the removal of basic amino acid extensions from recombinant proteins, thereby aiding in protein purification processes. Its specificity and efficiency make it an invaluable tool in the production of therapeutic proteins and peptides.

See Also

• Enzyme
• Protein digestion
• Pancreas
• Amino acid
• Zymogen
• Trypsin