This paper explores the proton pumping function of cytochrome c oxidase [ferrocytochrome-c:oxygen oxidoreductase (EC 1.9.3.1)] based upon redox linkage at the "high-potential" CuB center. A model is proposed that is derived from a redox-linked ligand exchange mechanism previously described for the CuA site. Qualitative analysis of this mechanism indicates that such a mechanism is feasible. Howe...

1. Mitochondria isolated from rat liver were disrupted with 0.3 per cent deoxycholate and a number of subfractions were isolated from this preparation by differential centrifugation. 2. The protein N, RNA and phospholipide content, as well as the succinoxidase, cytochrome c oxidase, adenylate kinase, and DPNH-cytochrome c reductase of these fractions were determined. 3. Two of these subfraction...

A preparation of reconstituted cytochrome oxidase vesicles in which the enzyme is oriented facing inwards (such that it cannot interact with external cytochrome c) is described. No oxidase activity is expressed by these vesicles unless they are disrupted, allowing influx of cytochrome c or exposure of the oxidase-binding site to the external medium. We have exploited this property to follow det...

The gram-positive endospore-forming bacterium Bacillus subtilis has, under aerobic conditions, a branched respiratory system comprising one quinol oxidase branch and one cytochrome oxidase branch. The system terminates in one of four alternative terminal oxidases. Cytochrome caa(3) is a cytochrome c oxidase, whereas cytochrome bd and cytochrome aa(3) are quinol oxidases. A fourth terminal oxida...