Synergistic effect of m-chloro-peroxybenzoic acid, sulfite and nitrite on the energy metabolism of Saccharomyces cerevisiae.

The respiration of starved Saccharomyces cerevisiae is inhibited 50% by 0.008 mM, 0.013 mM, or 0.06 mM m-chloro-peroxybenzoic acid (CPBA) when ethanol, glucose, or no external substrate is added, respectively. CPBA concentrations of 0.01-0.2 mM oxidize NADH or NADPH rapidly in vitro. Oxidation of reduced pyridine nucleotides might therefore contribute to the observed inhibition of respiration (oxygen uptake) in intact cells, in addition to the previously observed inhibition of glyceraldehyde-3-phosphate dehydrogenase and alcohol dehydrogenase. The inhibitory effect of CPBA on the activity of GAPDH and ADH, and the decreasing effect on the ATP level are synergistically potentiated when sulfite and/or nitrites is added together with CPBA, i.e., combinations of these substances are more effective than expected from the sum of effectivity of the single substances