[Functional characteristics of the electron transport chain in Candida mycoderma yeasts exposed to benzhydroxamic...

The effect of antimycin A and benzhydroxamic acid (BHA) on functioning of the electron transport system was studied with the resting cells of Candida mycoderma grown in a medium containing glucose and collected at the beginning of the deceleration phase. In the original ("control") cells, the processes of oxygen consumption were shown to be mediated mainly by the phosphorylating electron transport chain. When the cells were incubated withe glucose, the cyanide resistant electron transport chain (CRETC) started to operate in these processes. Antimycin A stimulated the operation of CRETC. BHA blocked CRETC and, at the same time, prevented the participation of pyridine nucleotides (PN) in the processes of oxygen utilization. Apparently, electron donors (or reduced equivalents) in the electron transport chain were flavin enzymes operating in the cytochrome b region of the chain instead of PN. Similar changes in the electron transport system (when PN were not involved in the processes of oxygen utilization) were observed if resting cells were incubated in the presence of ethanol.