title: Genetic determination of the constitutive biosynthesis of phospho- -glucosidase A in Escherichia coli K-12.
abstract: Escherichia coli wild-type cells form constitutively the enzyme phospho-beta-glucosidase A, which has a high affinity for phosphorylated aromatic beta-glucosides and a low affinity for phosphorylated beta-methyl-glucoside. Phospho-beta-glucosidase B and beta-glucoside permease I are formed in aromatic beta-glucoside-fermenting mutants. Mutants lacking phospho-beta-glucosidases A and B have been isolated. These mutants showed a reduced rate of inducibility of the beta-glucoside permease I. The restoration of phospho-beta-glucosidase A or B activity resulted in an increased rate of induction of the beta-glucoside permease I. The presence of the phospho-beta-glucosidases was not required for the constitutive biosynthesis of the beta-glucoside permease. Mutants selected for growth on beta-methyl-glucoside as carbon source showed an increased level of constitutive phospho-beta-glucosidase A activity. Gene bglD, the structural gene for phospho-beta-glucosidase A, was mapped between the pyrE locus and the cluster bgl loci, whereas bglE, the regulatory site determining the hyperproduction of phospho-beta-glucosidase A, was mapped between the bgl and ilv clusters. The bglE locus appears to have a regulatory effect on the expression of the bglD gene.
mesh_terms: D002247:Carbon Isotopes; D002874:Chromosome Mapping; D002876:Chromosomes, Bacterial; D003227:Conjugation, Genetic; D003470:Culture Media; D004926:Escherichia coli / Q000201:enzymology* / Q000378:metabolism; D005796:Genes; D005827:Genetics, Microbial; D005838:Genotype; D005959:Glucosidases / Q000096:biosynthesis*; D006027:Glycosides / Q000378:metabolism; D026901:Membrane Transport Proteins / Q000378:metabolism; D009154:Mutation / Q000187:drug effects; D010641:Phenotype; D013997:Time Factors; D014161:Transduction, Genetic
chemical_list: D002247:Carbon Isotopes; D003470:Culture Media; D006027:Glycosides; D026901:Membrane Transport Proteins; D005959:Glucosidases