Exopeptidase
Exopeptidase — A protease that cleaves amino acids from the ends of a peptide chain, including aminopeptidases (N-terminal) and carboxypeptidases (C-terminal).
What Is an Exopeptidase?
An exopeptidase is an enzyme that cleaves amino acid residues from the terminus of a peptide chain. Aminopeptidases remove residues from the N-terminus; carboxypeptidases remove from the C-terminus. Together with endopeptidases, exopeptidases complete the proteolytic degradation of peptides to individual amino acids.
Types and Relevance
- Aminopeptidase N (APN/CD13): Removes N-terminal residues sequentially. Major peptide-degrading enzyme on cell surfaces and in serum
- Carboxypeptidase A/B: Remove C-terminal residues (A: hydrophobic, B: basic). Active in GI tract and plasma
- DPP-IV: Removes N-terminal dipeptides from peptides with Pro/Ala at position 2 (GLP-1, CJC-1295)
Protection Strategies
N-terminal acetylation or D-amino acid substitution blocks aminopeptidases. C-terminal amidation blocks carboxypeptidases. Both modifications are standard in synthetic peptide design for half-life extension.
Frequently Asked Questions
What is Exopeptidase?
A protease that cleaves amino acids from the ends of a peptide chain, including aminopeptidases (N-terminal) and carboxypeptidases (C-terminal).
Why is Exopeptidase important in peptide research?
Exopeptidase is a fundamental concept in biochemistry as it relates to peptide science. It directly influences experimental design, compound characterization, and the reliability of research outcomes across biochemistry and molecular biology disciplines.