| Abstract: | Escherichia coli mutant devoid of fructosespecific factor III (factor IIIfru) of phosphoenolpyruvate (PEP) carbohydrate phosphotransferase system was isolated. The mutation fruB was localized on 46 min of chromosomal map of Escherichia coli in the fru-operon region. The mutant bacteria are unable to accumulate fructose. PEP-dependent phosphorylation of this carbohydrate in cellular extracts was considerably decreased. The mutational damage of factor IIIfru results in the suppression of beta-galactosidase synthesis. The impaired synthesis of the enzyme was partially resistant to glucose catabolite repression. However, the deficiency was suppressed by addition of exogenous cyclic AMP. The adenylatecyclase activity in fruB mutant was found to be 50% lower as compared with the one in the parent strain. |
