{PDOC00548}
{PS00631; CYTOSOL_AP}
{BEGIN}
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* Cytosol aminopeptidase signature *
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Cytosol  aminopeptidase is a eukaryotic cytosolic  zinc-dependent exopeptidase
that catalyzes  the removal  of unsubstituted  amino-acid  residues  from  the
N-terminus of proteins. This enzyme is  often  known as leucine aminopeptidase
(EC 3.4.11.1) (LAP)  but  has  been shown [1]  to  be  identical  with  prolyl
aminopeptidase (EC 3.4.11.5). Cytosol aminopeptidase is a hexamer of identical
chains, each of which binds two zinc ions.

Cytosol aminopeptidase is highly similar to Escherichia coli pepA, a manganese
dependent aminopeptidase.  Residues  involved  in  zinc ion-binding [2] in the
mammalian enzyme are  absolutely  conserved in pepA where they presumably bind
manganese. Most bacterial species contain a pepA-type enzyme.

As a signature pattern  for these  enzymes, we  selected a perfectly conserved
octapeptide which  contains  two  residues  involved in binding metal ions: an
aspartate and a glutamate.

-Consensus pattern: [NS]-[TS]-D-A-E-G-R-[LVMI]
                    [The D and the E are zinc/manganese ligands]
-Sequences known to belong to this class detected by the pattern: ALL.
-Other sequence(s) detected in Swiss-Prot: NONE.

-Note: These proteins belong to family M17 in the classification of peptidases
 [3,E1].

-Last update: April 2006 / Pattern revised.

[ 1] Matsushima M., Takahashi T., Ichinose M., Miki K., Kurokawa K.,
     Takahashi K.
     "Structural and immunological evidence for the identity of prolyl
     aminopeptidase with leucyl aminopeptidase."
     Biochem. Biophys. Res. Commun. 178:1459-1464(1991).
     PubMed=1908238
[ 2] Burley S.K., David P.R., Sweet R.M., Taylor A., Lipscomb W.N.
     "Structure determination and refinement of bovine lens leucine
     aminopeptidase and its complex with bestatin."
     J. Mol. Biol. 224:113-140(1992).
     PubMed=1548695
[ 3] Rawlings N.D., Barrett A.J.
     "Evolutionary families of metallopeptidases."
     Methods Enzymol. 248:183-228(1995).
     PubMed=7674922
[E1] https://www.uniprot.org/docs/peptidas

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