IUBMB Enzyme Nomenclature


Accepted name: SpoIVB peptidase

Reaction: Self-cleaves Val52Asn53, Ala62Phe63 and Val74Thr75 at the N-terminus of SpoIVB

Other name(s): sporulation factor IV B protease

Comments: This enzyme plays a central role in a regulatory checkpoint (the σK checkpoint), which coordinates gene expression during the later stages of spore formation in Bacillus subtilis [1,3]. The enzyme activates proteolytic processing of a sporulation-specific sigma factor, pro-σK, to its mature and active form, σK, by self-cleavage [1,3]. The enzyme is also subject to secondary proteolysis, which presumably inactivates SpoIVB [3]. The enzyme is also essential for the formation of heat-resistant spores. Belongs in peptidase family S55.

Links to other databases: BRENDA, EXPASY, KEGG, MEROPS, Metacyc, CAS registry number: 296241-18-4


1. Wakeley, P.R., Dorazi, R., Hoa, N.T., Bowyer, J.R. and Cutting, S.M. Proteolysis of SpolVB is a critical determinant in signalling of pro-σK processing in Bacillus subtilis. Mol. Microbiol. 36 (2000) 1336-1348. [PMID: 10931284]

2. Hoa, N.T., Brannigan, J.A. and Cutting, S.M. The PDZ domain of the SpoIVB serine peptidase facilitates multiple functions. J. Bacteriol. 183 (2001) 4364-4373. [PMID: 11418578]

3. Hoa, N.T., Brannigan, J.A. and Cutting, S.M. The Bacillus subtilis signaling protein SpoIVB defines a new family of serine peptidases. J. Bacteriol. 184 (2002) 191-199. [PMID: 11741860]

4. Dong, T.C. and Cutting, S.M. SpoIVB-mediated cleavage of SpoIVFA could provide the intercellular signal to activate processing of pro-σK in Bacillus subtilis. Mol. Microbiol. 49 (2003) 1425-1434. [PMID: 12940997]

[EC created 2006]

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