[Respiratory chain of Candida mycoderma]

The respiration chain of the yeast Candida mycoderma was studied during its growth on glucose. Electrons can be transported from the pyridine nucleotide (PN) pool to oxygen by two pathways, as was shown in experiments with intact cells on the basis of inhibitory analysis of respiration and the extent of reduction of electron carriers. The first pathway is inhibited by cyanide and antimycin A; it includes PN, flavoprotein, (FP) and cytochromes b, c and a + a3. The second pathway of electron transport is resistant to cyanide (CrPET), includes PN and FP, lacks cytochromes, and is blocked by salicyl- or benzhydroxamic acid. Two flavoprotein NADH-dehydrogenases are present in the cells of C. mycoderma: one is sensitive to rotenone, the other is resistant to it. The terminal electron acceptor can be not only O2, but also H2O2; in the latter case, electron transport involves PN, FP, and cytochromes b and c. At the exponential growth phase, only the first pathway of electron transport, including rotenone-resistant NADH-dehydrogenase, functions. At the phase when the rate of growth decreased, both pathways of electron transport and the two dehydrogenases are involved. At the stationary phase, mainly CrPET functions, but both NADH-dehydrogenases participate.