IUBMB Enzyme Nomenclature


Accepted name: plastoquinol—plastocyanin reductase

Reaction: plastoquinol + 2 oxidized plastocyanin + 2 H+[side 1] = plastoquinone + 2 reduced plastocyanin + 2 H+[side 2]

Other name(s): plastoquinol/plastocyanin oxidoreductase; cytochrome b6/f complex; cytochrome b6/ complex

Systematic name: plastoquinol:oxidized-plastocyanin oxidoreductase

Comments: Contains two b-type cytochromes, two c-type cytochromes (cn and f), and a [2Fe-2S] Rieske cluster. Cytochrome c-552 can act as acceptor instead of plastocyanin, but more slowly. In chloroplasts, protons are translocated through the thylakoid membrane from the lumen to the stroma.

Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, PDB, CAS registry number: 79079-13-3


1. Hurt, E. and Hauska, G. A cytochrome f/b6 complex of five polypeptides with plastoquinol-plastocyanin-oxidoreductase activity from spinach chloroplasts. Eur. J. Biochem. 117 (1981) 591-595. [PMID: 6269845]

2. Cramer, W.A. and Zhang, H. Consequences of the structure of the cytochrome b6f complex for its charge transfer pathways. Biochim. Biophys. Acta 1757 (2006) 339-345. [PMID: 16787635]

[EC created 1984 as EC, transferred 2011 to EC]

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