[Cyanide-resistant respiration in Torulopsis candida]

The effect of cyanide and the inhibitors of cyanide-resistant oxidase--hydroxamic acids on endogenous respiration and oxidation of a number of substrates by Torulopsis candida resting cells taken at different stages of growth on glucose and hexadecane was studied and made it possible to arrive at the following conclusions. 1. The effect of cyanide on endogenous respiration of T. candida differs during its growth on glucose and hexadecane. On hexadecane, irrespective of the growth phage, cyanide inhibits endogenous respiration by 70--75%. On glucose, cyanide inhibits endogenous respiration not more than by 35% and only at the exponential growth phase whereas it stimulates endogenous respiration in the course of other growth stages. 2. The effect of cyanide on respiration of the resting cells of T. candida which oxidize glucose, hexadecane, primary alcohols and tetradecanoic acid hardly depends on the growth stage. It is determined mainly by the nature of a substrate to be oxidized. 3. Hydroxamic acid have no effect on the cell respiration in the absence of cyanide. However, in its presence, they entirely inhibit both endogenous respiration and oxidation of the aforementioned substrates. 4. Under almost all above experimental conditions, the sensitivity of cell respiration to cyanide changes only slightly at different stages of growth on either glucose or hexadecane. This feature markedly distinguishes T. candida among other cyanide-resistant yeasts.