Involvement of glutathione in the regulation of respiratory oscillation during a continuous culture of Saccharomyces cerevisiae.

Respiratory oscillation occurred during aerobic continuous culture of Saccharomyces cerevisiae. During oscillation, phase-related changes in NAD(P)H and GSH levels occur. Perturbation of oscillation and inhibition of respiration occurred when GSH or GSSG was injected; however, there was a phase delay in perturbation in the case of an injection during high respiration. The perturbation phase delay was not apparent when a combination of DL-buthionine-(S,R)-sulphoximine, GSH and 5-nitro-2-furaldehyde was injected. Perturbation by GSH injection caused the intracellular GSH concentration to increase, the GSSG concentration to decrease and the cessation of ethanol uptake. NAD(P)H during perturbation was inversely related to dissolved oxygen. Perturbation by calcium pantothenate and pyridoxal-HCl caused a period of enhanced respiration before oscillation returned. These results suggest that the NAD+/NADH redox is not directly involved in oscillation control and regulation involves glutathione metabolism. Possible regulation points include alcohol dehydrogenase inhibition and/or respiratory-chain inhibition.