Reduction of Respiratory‐Chain Cytochrome b by Lactate in Saccharomyces cerevisiae

Abstract

Cytochrome b of yeast mitochondria can be reduced by a part of the electrons resulting from the oxidation of lactate enantiomers. The respiration of d‐lactate and l‐lactate is 30–40% inhibited by antimycin A. Reduction of cytochrome b is observed in submitochondrial particles in the presence of low concentration of d‐lactate and l‐lactate (half‐optimal concentration of 4.7 mM and 2.4 mM respectively) in the presence of different bc1 inhibitors. Reduction of cytochrome b and c1 occurs in purified complex III of yeast in the presence of l‐lactate and added l‐lactate:NAD+ oxidoreductase. In the particles obtained from yeast grown in lactate the oxidation of l‐lactate involves the reduction of a pigment absorbing at 558 nm. Copyright © 1982, Wiley Blackwell. All rights reserved