- Source: Exopeptidase
An exopeptidase is any peptidase that catalyzes the cleavage of the terminal (or the penultimate) peptide bond; the process releases a single amino acid, dipeptide or a tripeptide from the peptide chain. Depending on whether the amino acid is released from the amino or the carboxy terminal (N-terminus or C-terminus), an exopeptidase is further classified as an aminopeptidase or a carboxypeptidase, respectively. Thus, an aminopeptidase, an enzyme in the brush border of the small intestine, will cleave a single amino acid from the amino terminal, whereas carboxypeptidase, which is a digestive enzyme present in pancreatic juice, will cleave a single amino acid from the carboxylic end of the peptide.
Some examples of exopeptidases include:
Carboxypeptidase A - cleaves C-terminal Phe, Tyr, Trp, or Leu
Carboxypeptidase B - cleaves C-terminal Lys or Arg
Aminopeptidase - cleaves any N-terminal amino acid
Prolinase - cleaves N-terminal Pro from dipeptides
Prolidase - cleaves C-terminal Pro from dipeptides
See also
The Proteolysis Map
Endopeptidase
Edman degradation
Dansyl chloride
Protease
External links
Exopeptidases at the U.S. National Library of Medicine Medical Subject Headings (MeSH)