Ruthenium(II) and iridium(III) bis(terpyridine) complexes were prepared with maleimide functionalities in order to site-specifically modify yeast iso-1 cytochrome c possessing a single cysteine residue available for modification (CYS102). Single X-ray crystal structures were solved for aniline and maleimide Ru(II) 3 and Ru(II) 4, respectively, providing detailed structural detail of the complex...

Cytochrome oxidase catalyses the reduction of oxygen to water. The mitochondrial enzyme contains up to 13 subunits, 11 in yeast, of which three, Cox1p, Cox2p and Cox3p, are mitochondrially encoded. The assembly pathway of this complex is still poorly understood. Its study in yeast has been so far impeded by the rapid turnover of unassembled subunits of the enzyme. In the present study, immunobl...

An assay has been developed to study the steady-state kinetics of the reduction of cytochrome c by purified beef heart mitochondrial cytochrome c reductase (cytochrome bc(1) complex, complex III). An analogue of coenzyme Q(2) (2,3-dimethoxy-5-methyl-6-decylhydroquinone) was employed as an antimycin-sensitive reductant. The kinetics of reaction of ten different mono(4-carboxy-2,6-dinitrophenyl) ...

Cytochrome P-450 was originally found in anaerobically grown baker’s yeast and to a lesser extent in yeast grown aerobically to the end of the exponential phase of growth in relatively high-glucose medium (4 %, w/v) (Lindenmeyer & Smith, 1964). Good yields of cytochrome P-450 can be obtained under conditions of glucose repression of mitochondria, for example in 20% glucose medium, and the prese...

In yeast the reduction of ferricytochrome c by reduced triphosphopyridine nucleotide (TPNH2) is catalyzed by a flavoprotein, cytochrome c reductase, which contains flavin mononucleotide (FMN, riboflavin phosphate) as the prosthetic group (1). In animal tissue the reduction of ferricytochrome c by TPNHz has not yet been reported, although the reaction with reduced diphosphopyridine nucleotide (D...

Thermal denaturation studies as a function of pH were carried out on wild-type iso-I-cytochrome c and three variants of this protein at the solvent-exposed position 73 of the sequence. By examining the enthalpy and T, at various pH values, the heat capacity increment (AC,,), which is dominated by the degree of change in nonpolar hydration upon protein unfolding, was found for the wild type wher...