%0 Journal Article %A Bolivar, F. %A Galván, Matilde %A Martuscelli, J. %T Biochemical and Genetic Characterization of a Carbamyl Phosphate Synthetase Mutant of Escherichia coli K12 %D 1976 %J Microbiology, %V 94 %N 1 %P 142-148 %@ 1465-2080 %R https://doi.org/10.1099/00221287-94-1-142 %I Microbiology Society, %X Summary: An unusual Escherichia coli k12 mutant for carbamyl phosphate synthetase is described. The mutation was generated by bacteriophage Mu1 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. It was possible to distinguish serologically between Phytophthora cinnamomi and Phytophthora cambivora and the Phytophthora cryptogea-Phytophthora drechsleri group. The absence of consistent serological variation between P. cryptogea and P. dreschsleri is consistent with the suggestion (Bumbieris, 1974) that P. cryptogea and P. drechsleri should be considered as one species. %U https://www.microbiologyresearch.org/content/journal/micro/10.1099/00221287-94-1-142