Identification of a coenzyme A--glutathione disulfide (DSI), a modified coenzyme A disulfide (DSII), and a NADPH-dependent coenzyme A--glutathione disulfide reductase in E. coli.

The nucleotides DSI and DSII induced during a slowdown in growth of E. coli have been characterized using chemical and biochemical analysis and by enzymic and alkaline fragmentation. DSI consists a coenzyme A and glutathione joined by a disulfide linkage. DSI could be isolated either containing Fe(III) with an A250:260 ratio of 1.05 or not containing iron with an A250:260 of 0.87. DSII (isolated in 10% the yield of DSI) is a coenzyme A disulfide dimer that also contains two molecules of glutamic acid. DSI was a substrate for NADPH-dependent CoAS-SG reductase (EC 1.6.4.6) which was present in crude extracts of E. coli. The specific activity of CoAS-SG reductase increased during growth from early log phase into stationary phase and during a shift from aerobic to anaerobic growth.