Peptidase S51, dipeptidase E (IPR023172)

Short name: Peptidase_S51_dipeptidase-E

Overlapping homologous superfamilies

Family relationships

  • Peptidase S51 (IPR005320)
    • Peptidase S51, dipeptidase E (IPR023172)


Proteolytic enzymes that exploit serine in their catalytic activity are ubiquitous, being found in viruses, bacteria and eukaryotes [PMID: 7845208]. They include a wide range of peptidase activity, including exopeptidase, endopeptidase, oligopeptidase and omega-peptidase activity. Many families of serine protease have been identified, these being grouped into clans on the basis of structural similarity and other functional evidence [PMID: 7845208]. Structures are known for members of the clans and the structures indicate that some appear to be totally unrelated, suggesting different evolutionary origins for the serine peptidases [PMID: 7845208].

Not withstanding their different evolutionary origins, there are similarities in the reaction mechanisms of several peptidases. Chymotrypsin, subtilisin and carboxypeptidase C have a catalytic triad of serine, aspartate and histidine in common: serine acts as a nucleophile, aspartate as an electrophile, and histidine as a base [PMID: 7845208]. The geometric orientations of the catalytic residues are similar between families, despite different protein folds [PMID: 7845208]. The linear arrangements of the catalytic residues commonly reflect clan relationships. For example the catalytic triad in the chymotrypsin clan (PA) is ordered HDS, but is ordered DHS in the subtilisin clan (SB) and SDH in the carboxypeptidase clan (SC) [PMID: 7845208, PMID: 8439290].

This entry represents serine peptidases belonging to MEROPS peptidase family S51 (dipeptidase E, clan PC). They hydrolyse peptides bond in dipeptides where the first amino acid is aspartate [PMID: 9928148]. The three-dimensional structure of Salmonella typhimurium aspartyl dipeptidase, peptidase E, has been reported at 1.2A resolution. The structure of this 25 kDa enzyme consists of two mixed b-sheets forming a V, flanked by six a-helices. The active site contains a Ser-His-Glu catalytic triad [PMID: 11106384].

GO terms

Biological Process

No terms assigned in this category.

Molecular Function

GO:0016805 dipeptidase activity

Cellular Component

No terms assigned in this category.

Contributing signatures

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