Regulation of Succinate Dehydrogenase in Escherichia coli

Abstract

SUMMARY: Washed suspensions of Escherichiacoli oxidized succinate when previously grown on succinate but not on glucose. A slower rateof oxidation occurred with bacteria grown with peptone as carbon source. These differences were due to alterations in the level of succinate dehydrogenase activity. Glucose repressed the biosynthesis ofthe enzyme, whereas succinate acted as specific inducer and did not increase the activity of fumarate hydratase, malate dehydrogenase or NADH dehydrogenase. Aerobic growth also increased the levels of membrane-bound succinate dehydrogenase. Induction of succinate dehydrogenase by added succinate followed the expected kinetics. Addition of glucose caused a decline in the rate of biosynthesis of succinate dehydrogenase. Succinate dehydrogenase appears to play an important respiratory role since amytal(an NADH-oxidase inhibitor) inhibited growth only slightly when succinate was used as carbon source ascompared to the strong inhibition of growth when glucose was used as carbon source.