Levels of coenzyme A – glutathione mixed disulfide in Escherichia coli

Abstract

The pool of CoA-glutathione mixed disulfide (CoASSG) rapidly increased 2.0 times in response to O2 starvation and 1.5 times in response to glucose starvation but did not change following NH3 starvation. The increase in the CoASSG pool resulted from an increase in the CoASSG fraction of the CoA pool from 42 to 66-93%. Fluoride, cyanide, chloramphenicol and rifampicin all caused similar increases. Aerobic growth on fermentable sugars resulted in CoASSG making up 40-55% of the CoA pool while growth on nonfermentable C sources or anaerobic fermentation resulted in CoASSG replacing acetyl CoA and free CoA to make up 85-95% of the CoA pool. The CoASSG:ATP ratio varied inversely with the growth in 2 groupings of C sources made up of either fermentable or nonfermentable molecules. Cultures grown aerobically on fermentable sugars exhibited a lower CoASSG:ATP ratio reflecting the lower proportion of CoASSG in the CoA pool.