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cytosol aminopeptidase; leucine aminopeptidase-3; LAP3; proline aminopeptidase; peptidase S (LAP3, LAPEP, PEPS)
Function:
- presumably involved in the processing & regular turnover of intracellular proteins
- catalyzes the removal of unsubstituted N-terminal amino acids from various peptides
- removes mostly leucine & other hydrophobic residues
- release of an N-terminal amino acid, Xaa-|-Yaa-, in which Xaa is preferably Leu, but may be other amino acids including pro although not Arg or Lys, & Yaa may be pro
- amino acid amides & methyl esters are also readily hydrolyzed, but rates on arylamides are exceedingly low
- release of N-terminal proline from a peptide
Cofactor:
- binds 2 Zn+2 per subunit
- one Zn+2 ion is tightly bound & essential for enzyme activity; the 2nd metal coordination site can be occupied by Zn+2, Mg+2 or Mn+2 to give enzymes of different activities (putative)
Structure:
- homohexamer
- belongs to the peptidase M17 family
Compartment: cytoplasm
Alternative initiation:
- named isoforms=2
Expression:
- upregulated 3-fold after 14 days of environmental enrichment in mice [3].
Pathology:
- serum levels elevated in hepatobiliary disease
- no elevation of serum levels in bone disease
Note: initiator methionine is removed
General
aminopeptidase
oligomerizing protein
Properties
SIZE: entity length = 519 aa
MW = 56 kD
COMPARTMENT: cytoplasm
MOTIF: Zn+2-binding site
SITE: 282-282
Zn+2-binding site
SITE: 287-287
lysine residue {K294}
Zn+2-binding site
SITE: 305-305
Zn+2-binding site
SITE: 364-364
Zn+2-binding site
SITE: 366-366
arginine residue {R368}
Database Correlations
OMIM 151300
UniProt P28838
ENZYME correlations
References
- Taylor A.
Aminopeptidases: structure and function.
FASEB J. 1993 Feb 1;7(2):290-8. Review.
PMID: 8440407
- Clinical Diagnosis & Management by Laboratory Methods,
J.B. Henry (ed), W.B. Saunders Co., Philadelphia,
PA. 1991, pg 263
- Rampon C, Jiang CH, Dong H, Tang YP, Lockhart DJ, Schultz PG,
Tsien JZ, Hu Y.
Effects of environmental enrichment on gene expression in the
brain.
Proc Natl Acad Sci U S A. 2000 Nov 7;97(23):12880-4.
PMID: 11070096
- UniProt :accession P28838