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Protonic sidedness of the binuclear iron‐copper centre in cytochrome oxidase
Author(s) -
Wikström Mårten
Publication year - 1988
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(88)80741-5
Subject(s) - cytochrome c oxidase , copper , chemistry , biochemistry , enzyme , organic chemistry
The oxidised (ferric‐cupric) binuclear centre of cytochrome oxidase is converted into two other states, presumably ferryl‐cupric (F) and ferric‐peroxy‐cupric (P), by energy‐dependent reversed electron transfer from the centre (and water) to cytochrome c [(1981) Proc. Natl. Acad. Sci. USA 78, 4051–4054; (1987) Chem. Scr. 27B, 53–58]. This sequence of events represents a partial reversal of the O 2 reduction catalysed by the centre. Here it is shown that the strong pH‐dependence of these reactions is exerted specifically from the matrix (M) side of the inner mitochondrial membrane. This proves un‐equivocally that the binuclear centre generates protonmotive force by means of its vectorial accessibility for electrons and protons.