Peptidase M18 (IPR001948)

Short name: Peptidase_M18

Overlapping homologous superfamilies


Family relationships


This group of metallopeptidases belong to the MEROPS peptidase family M18, (clan MH). The proteins have two catalytic zinc ions at the active site, bound by His/Asp, Asp, Glu, Asp/Glu and His. The catalysed reaction involves the release of an N-terminal aminoacid, usually neutral or hydrophobic, from a polypeptide [PMID: 7674922].

The type example is aminopeptidase I from Saccharomyces cerevisiae (Baker's yeast), the sequence of which has been deduced, and the mature protein shown to consist of 469 amino acids [PMID: 2651436]. A 45-residue presequence contains both positively- and negatively-charged and hydrophobic residues, which could be arranged in an N-terminal amphiphilic alpha-helix [PMID: 2651436]. The presequence differs from signal sequences that direct proteins across bacterial plasma membranes and endoplasmic reticulum or into mitochondria. It is unclear how this unique presequence targets aminopeptidase I to yeast vacuoles, and how this sorting utilises classical protein secretory pathways [PMID: 2651436].

GO terms

Biological Process

GO:0006508 proteolysis

Molecular Function

GO:0004177 aminopeptidase activity
GO:0008270 zinc ion binding

Cellular Component

No terms assigned in this category.

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.