Cytochrome oxidase is a multisubunit, intrinsic membrane protein with a complex function that includes oxidation of cytochrome c, reduction of oxygen and generation of a membrane potential. To clarify the relationship of its normal function to protein and membrane structure, we have examined the kinetic behavior of rat liver cytochrome oxidase in the intact inner mitochondrial membrane and in d...

subunits that always include one or more homologues of Ulrich Gohlke, Antony Warne and the mitochondrially coded eukaryotic proteins (Saraste, Matti Saraste 1990). European Molecular Biology Laboratory, Biological Structures The Gram-negative eubacterium Escherichia coli posProgramme, Meyerhofstrasse 1, Postfach 10.2209, sesses a branched respiratory chain. Depending on the D-69012 Heidelberg, ...

NADPH oxidase activity was solubilized by detergent treatment of subcellular particles obtained from guinea-pig peritoneal macrophages stimulated with phorbol myristate acetate. Gel filtration of the material containing the NADPH oxidase activity gave two peaks of proteins, one of which eluted with the void and the other with the included volume of an AcA 22 column. The material eluted in the v...

Nitric oxide (NO) is an intercellular signaling molecule; among its many and varied roles are the control of blood flow and blood pressure via activation of the heme enzyme, soluble guanylate cyclase. A growing body of evidence suggests that an additional target for NO is the mitochondrial oxygen-consuming heme/copper enzyme, cytochrome c oxidase. This review describes the molecular mechanism o...

The mechanism of cytochrome induction in human cells was investigated. Cultured fibroblasts grown in low oxygen had markedly reduced contents of cytochromes A + A(3), B, and C + C(1) as measured by absorption spectra. Chloramphenicol but not cycloheximide or actinomycin blocked the initial increase in cytochrome oxidase activity in cells shifted from low to ambient oxygen, suggesting that initi...

TO THE EDITOR: We are pleased that the authors have read our paper (2) and consider it of sufficient importance to critique it (1). There is an error in our program: the rate constants k4a and k4b are interchanged in Eq. A15. The error was introduced before fitting of the equations to the cytochrome c oxidase data. Fortunately, Eq. A15 is only used for calculating the turnover number for cytoch...

Strains of the yeast Saccharomyces cerevisiae disrupted in YCOX4, the nuclear gene encoding cytochrome c oxidase subunit IV, do not assemble a functional or spectrally visible oxidase. We report the characterization of a yeast strain, RM1, expressing a mutated YCOX4 gene which is temperature sensitive for respiration at 37 "C, but incorporates cytochrome aas over all growth temperatures. The mu...