Insulin action on Escherichia coli. Regulation of the adenylate cyclase and phosphotransferase enzymes.

Insulin on Escherichia coli was studied using wild type E. coli B/r and K12 strains and a number of phosphoenolpyruvate phosphotransferase mutants. In vivo, the effects of insulin on the differential rate of tryptophanase synthesis, the rate of alpha-methylglucoside uptake and the rate of growth on glucose were determined in E. coli B/r. In vitro, the effect of insulin on the adenylate cyclase and the phosphotransferase activities was determined using toluenized cell preparations of E. coli B/r, E. coli K12 and phosphotransferase mutant strains. The specificity of insulin action on E. coli was determined using glucagon, vasopressin and somatropin as well as insulin antisera. Results show the specific action of insulin on E. coli, inhibiting tryptophanase induction and adenylate cyclase activity, while stimulating growth on glucose and uptake and phosphorylation of alpha-methylglucoside.