Contains two b-type cytochromes, two c-type cytochromes (cn and f), and a [2Fe-2S] Rieske cluster. The enzyme plays a key role in photosynthesis, transferring electrons from photosystem II (EC 184.108.40.206) to photosystem I (EC 220.127.116.11). Cytochrome c-552 can act as acceptor instead of plastocyanin, but more slowly. In chloroplasts, protons are translocated through the thylakoid membrane from the stroma to the lumen. The mechanism occurs through the Q cycle as in EC 18.104.22.168, quinol—cytochrome-c reductase (complex III) and involves electron bifurcation.
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. [DOI] [PMID: 6269845]
Cramer, W.A. and Zhang, H. Consequences of the structure of the cytochrome b6f complex for its charge transfer pathways. Biochim. Biophys. Acta1757 (2006) 339–345. [DOI] [PMID: 16787635]
[EC 22.214.171.124 created 1984 as EC 126.96.36.199, transferred 2011 to EC 188.8.131.52]