Carboxypeptidase

Functions

The first carboxypeptidases studied were those involved in the growth factor production, wound healing, reproduction, and many other processes.

Classification

By active site mechanism

Carboxypeptidases are usually classified into one of several families based on their active site mechanism.

• Enzymes that use a metal in the active site are called "metallo-carboxypeptidases".
• Other carboxypeptidases that use active site serine residues are called "serine carboxypeptidases".
• Those that use an active site thiol carboxypeptidases").

These names do not refer to the selectivity of the amino acid that is cleaved.

By substrate preference

Another classification system for carboxypeptidases refers to their substrate preference.

• In this classification system, carboxypeptidases that have a stronger preference for those amino acids containing carboxypeptidase A (A for aromatic/aliphatic).
• Carboxypeptidases that cleave positively charged amino acids (basic).

A metallo-carboxypeptidase that cleaves a C-terminal glutamate from the peptide N-acetyl-L-aspartyl-L-glutamate is called "glutamate carboxypeptidase".

A serine carboxypeptidase that cleaves the C-terminal residue from peptides containing the sequence -Pro-Xaa (Pro is proline, Xaa is any amino acid on the C-terminus of a peptide) is called "prolyl carboxypeptidase".

Activation

Some, but not all, carboxypeptidases are initially produced in an inactive form; this precursor form is referred to as a procarboxpeptidase. In the case of pancreatic carboxypeptidase A, the inactive zymogen form, pro-carboxypeptidase A, is converted to its active form - carboxypeptidase A - by the enzyme enteropeptidase. This mechanism ensures that the cells wherein pro-carboxypeptidase A is produced are not themselves digested.

See also

• Carboxypeptidase E
• Carboxypeptidase A

See also

• Enzyme category EC number 3.4
• Thrombin-activatable fibrinolysis inhibitor aka plasma carboxypeptidase B2
• bacterial transpeptidase, an alanine carboxypeptidase
• bradykinin is broken down among other enzymes by carboxypeptidase N
• D-Ala carboxypeptidase is a penicillin binding proteins
• Phenylalanine might inhibit carboxypeptidase A