Inhibition of membrane-bound cytochrome c oxidase by zinc ions: high-affinity Zn2+-binding site at the P-side of the membrane.
In the presence of the uncoupler, external zinc ions inhibit rapidly turnover of cytochrome c oxidase reconstituted in phospholipid vesicles or bound to the membrane of intact mitochondria. The effect is promoted by electron leaks into the oxidase during preincubation with Zn(2+). Inhibition of liposome-bound bovine cytochrome oxidase by external Zn(2+) titrates with a K(i) of 1+/-0.3 microM. Presumably, the Zn(2+)-binding group at the positively charged side is not reactive in the oxidized enzyme, but becomes accessible to the cation in some partially reduced state(s) of the oxidase; reduction of Cu(B) is tentatively proposed to be responsible for the effect.
Vygodina
Tatiana V
TV
A.N. Belozersky Institute, M.V. Lomonosov Moscow State University, Moscow 119992, Russia.
Zakirzianova
Wiolanta
W
Konstantinov
Alexander A
AA
D000818:Animals; D002413:Cations, Divalent / Q000494:pharmacology; D002417:Cattle; D003300:Copper / Q000737:chemistry / Q000494:pharmacology; D003576:Electron Transport Complex IV / Q000037:antagonists & inhibitors* / Q000737:chemistry; D008081:Liposomes / Q000737:chemistry; D008566:Membranes / Q000737:chemistry / Q000201:enzymology; D008928:Mitochondria / Q000201:enzymology; D010743:Phospholipids / Q000737:chemistry; D051381:Rats; D015032:Zinc / Q000737:chemistry / Q000494:pharmacology*
D002413:Cations, Divalent; D008081:Liposomes; D010743:Phospholipids; D003300:Copper; D003576:Electron Transport Complex IV; D015032:Zinc