Open AccessBiochemical and Genetic Characterization of a Carbamyl Phosphate Synthetase Mutant of Escherichia coli K12
Author(s) -
Francisco Bolívar,
Manuel González Galván,
Jaime Martuscelli
Publication year - 1976
Publication title -
journal of general microbiology/journal of general microbiology
Language(s) - English
Resource type - Journals
eISSN - 2059-9323
pISSN - 0022-1287
DOI - 10.1099/00221287-94-1-142
Subject(s) - carbamyl phosphate , mutant , escherichia coli , arginine , uracil , biology , biochemistry , mutation , enzyme , microbiology and biotechnology , ornithine , gene , glutamine , ornithine transcarbamylase , dna , amino acid , urea cycle
An unusual Escherichia coli K12 mutant for carbamyl phosphate synthetase is described. The mutation was generated by bacteriophage MUI insertion and left a 5% residual activity of the enzyme using either ammonia or glutamine as donors. The mutation is recessive to the wild-type allele and maps at or near the pyrA gene, but the mutant requires only arginine and not uracil for growth. By a second block in the pyrB gene it was possible to shift the accumulated carbamyl phosphate to arginine biosynthesis. The Km values and the levels of ornithine activation and inhibition by UMP were normal in the mutant enzyme.