IUBMB Enzyme Nomenclature


Accepted name: C-terminal processing peptidase

Reaction: The enzyme shows specific recognition of a C-terminal tripeptide, Xaa-Yaa-Zaa, in which Xaa is preferably Ala or Leu, Yaa is preferably Ala or Tyr, and Zaa is preferably Ala, but then cleaves at a variable distance from the C-terminus. A typical cleavage is -Ala-AlaArg-Ala-Ala-Lys-Glu-Asn-Tyr-Ala-Leu-Ala-Ala. In the plant chloroplast, the enzyme removes the C-terminal extension of the D1 polypeptide of photosystem II

Other names: CtpA gene product (Synechocystis sp.); photosystem II D1 protein processing peptidase; protease Re; tail-specific protease; Tsp protease

Comments: Proteolytic processing of the D1 protein of photosystem II is necessary to allow the light-driven assembly of the tetranuclear manganese cluster, which is responsible for photosynthetic water oxidation. The recognition of the substrate is mediated by a PDZ domain, a small protein module that promotes protein-protein interactions by binding to internal or C-terminal sequences of their partner proteins. Type example of peptidase family S41.

Links to other databases: BRENDA, EXPASY, KEGG, MEROPS, Metacyc, PDB, CAS registry number: 216484-75-2 and 92480-11-0


1. Keiler, K.C. and Sauer, R.T. Tsp protease. In: Barrett, A.J., Rawlings, N.D. and Woessner, J.F. (Eds.), Handbook of Proteolytic Enzymes, Academic Press, London, 1998, pp. 460-461.

2. Beebe, K.D., Shin, J.N., Peng, J., Chaudhury, C., Khera, J. and Pei, D.H. Substrate recognition through a PDZ domain in tail-specific protease. Biochemistry 39 (2000) 3149-3155. [PMID: 10715137]

3. Liao, D.I., Qian, J., Chisholm, D.A., Jordan, D.B. and Diner, B.A. Crystal structures of the photosystem II D1 C-terminal processing protease. Nat. Struct. Biol. 7 (2000) 749-753. [PMID: 10966643]

[EC created 2001]

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