[Respiratory cyanide resistance in Candida lipolytica and the supersynthesis of citric acids].

The interrelationship between the cyanide resistance of respiratio and the process of citric acid synthesis was studied with various strains of Candida lipolytica. When the synthesis of citric acids was intensive, the respiration of cells was almost entirely inhibited by cyanide. The respiration became cyanide resistant only when the biosynthesis of citric acids was over. Induction of the cyanide resistance of respiration with antimycin A stopped the biosynthesis of citric acids. The cyanide resistance of respiration in yeast cultures incapable of considerable production of citric acids was displayed when the growth ceased. There was a strong direct correlation between the rate of citric acid synthesis and the degree of inhibition of the respiration by cyanide. It was concluded therefore that the process of citric acid overproduction could reset the reduction equivalents, thus making unnecessary the cyanide resistant pathway of electron transport.