title: Excretion of alkaline phosphatase by Escherichia coli K-12 pho constitutive mutants transformed with plasmids carrying the alkaline phosphatase structural gene.
abstract: Escherichia coli alkaline phosphatase constitutive mutants carrying a pst or a phoS mutation and a plasmid-bearing gene phoA+ excreted into the growth medium up to 50% of the total alkaline phosphatase production. This excretion was pH dependent and did not involve drastic modifications of the cell envelope. Alkaline phosphatase accounted for 80% of total released proteins. Amplification of gene phoA+ was a necessary condition for excretion to occur. When the beta-lactamase structural gene bla+ was coamplified with gene phoA+, both enzymes were excreted. pst-transformed excretory strains did not show the pleiotrophic phenotype previously described for lky mutants.
mesh_terms: D000469:Alkaline Phosphatase / Q000235:genetics / Q000378:metabolism*; D004262:DNA Restriction Enzymes / Q000378:metabolism; D004269:DNA, Bacterial / Q000032:analysis; D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics; D005796:Genes; D005798:Genes, Bacterial; D006863:Hydrogen-Ion Concentration; D009154:Mutation; D010957:Plasmids; D014170:Transformation, Genetic
chemical_list: D004269:DNA, Bacterial; D004262:DNA Restriction Enzymes; D000469:Alkaline Phosphatase