Isolation and characterization of the nuclear gene and gene product of COX12, the gene encoding subunit Vlb of cytochrome c oxidase of Saccharomyces cerevisiae

COX12 encodes subunit VIb of cytochrome c oxidase of Saccharomyces cerevisiae, is 41% identical to the homologous mammalian subunit and was a single copy gene. A ;A spectrally detectable cytochrome c oxidase was assembled in a ;An enzyme complex of cytochrome c oxidase comprised of a subpopulation of molecules present in solubized mitochondrial membranes could be purified. The purified enzyme of the deletion strain had a catalytic activity comparable to that of the purified wild type enzyme, but exhibited altered recombination kinetics with hydrogen cyanide compared to the wild type enzyme.