InterPro : IPR001733

Name  Peptidase S26B, eukaryotic signal peptidase Short Name  Peptidase_S26B
Type  Family Description  Proteolytic enzymes that exploit serine in their catalytic activity are ubiquitous, being found in viruses, bacteria and eukaryotes []. 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 []. 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 [].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 []. The geometric orientations of the catalytic residues are similar between families, despite different protein folds []. 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) [, ].This group of serine peptidases belong to MEROPS peptidase family S26 (signal peptidase I family, clan SF), subfamily S26B.Eukaryotic microsomal signal peptidase is involved in the removal of signalpeptides from secretory proteins as they pass into the endoplasmic reticulumlumen []. The peptidase is more complex than its mitochondrial and bacterial counterparts, containing a number of subunits, ranging from two in the chicken oviduct peptidase, to five in the dog pancreas protein []. They share sequence similarity with thebacterial leader peptidases (family S26A), although activity here is mediatedby a serine/histidine dyad rather than a serine/lysine dyad []. Archaeal signal peptidases also belong to this group.

Sequence Features

GO Displayer


InterPro protein domain ID --> Contigs



0 Child Features

2 Contains

Id Name Short Name Type
IPR019759 Peptidase S24/S26A/S26B Peptidase_S24_S26 Domain
IPR019756 Peptidase S26A, signal peptidase I, serine active site Pept_S26A_signal_pept_1_Ser-AS Active_site

0 Found In

0 Parent Features

2 Publications

First Author Title Year Journal Volume Pages
Rawlings ND Evolutionary families of peptidases. 1993 Biochem J 290 ( Pt 1) 205-18
Rawlings ND Families of serine peptidases. 1994 Methods Enzymol 244 19-61

To cite PlanMine, please refer to the following publication:

Rozanski, A., Moon, H., Brandl, H., Martín-Durán, J. M., Grohme, M., Hüttner, K., Bartscherer, K., Henry, I., & Rink, J. C.
PlanMine 3.0—improvements to a mineable resource of flatworm biology and biodiversity
Nucleic Acids Research, gky1070. doi:10.1093/nar/gky1070 (2018)