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Aminopeptidase B (EC 3.4.11.6).
1Laboratoire de Biochimie des Signaux Régulateurs Cellulaires et Moléculaires, Université Pierre et Marie Curie, Paris, France. foulon@ccr.jussieu.fr
The International Journal of Biochemistry & Cell Biology
|September 1, 1999
Summary
Aminopeptidase B, a zinc-dependent enzyme, cleaves specific amino acids from peptides and hydrolyzes leukotriene A4. It plays a role in precursor processing in various tissues and cellular locations.
Area of Science:
- Biochemistry
- Enzymology
- Cell Biology
Background:
- Aminopeptidase B (EC 3.4.11.6) is a zinc-dependent exopeptidase.
- It removes arginine and lysine residues from peptide N-termini.
- Structurally related to leukotriene A4 hydrolase.
Purpose of the Study:
- To investigate the enzymatic activity and substrate specificity of Aminopeptidase B.
- To explore the structural relationship between Aminopeptidase B and leukotriene A4 hydrolase.
- To elucidate the potential role of Aminopeptidase B in cellular precursor processing.
Main Methods:
- Analysis of primary structure.
- Enzyme activity assays with various peptide substrates.
- Hydrolysis assay with leukotriene A4.
- Tissue distribution analysis.
Main Results:
- Aminopeptidase B selectively cleaves Arg/Lys from peptide substrates like enkephalins and somatostatin.
- Demonstrated capacity of Aminopeptidase B to hydrolyze leukotriene A4.
- Enzyme is widely distributed and found on the plasma membrane in PC12 cells.
Conclusions:
- Aminopeptidase B is a bi-functional enzyme with roles in peptide processing and leukotriene metabolism.
- Its presence in various tissues and cellular compartments suggests a significant physiological function.
- Likely involved in final stages of precursor processing within the secretory pathway and/or at the plasma membrane.