title: Escherichia coli mutants deficient in guanine-xanthine phosphoribosyltransferase.
abstract: We studied the purine phosphoribosyltransferases (PRTases) of Escherichia coli and were able to isolate a mutant that is defective in its ability to convert guanine and xanthine to their respective ribonucleotides. The affected gene (gpt) lies between metD and proA and is 78.6% co-transducible with proA. Both this point mutant and a strain with a pro-lac deletion contain less than 2% of wild-type xanthine PRTase activity, yet still contain about 30% of wild-type guanine PRTase activity. Thus, the gpt gene is only one of at least two genes responsible for guanine PRTase activity in E. coli.
mesh_terms: D000225:Adenine / Q000378:metabolism; D002474:Cell-Free System; D004926:Escherichia coli / Q000201:enzymology* / Q000378:metabolism; D005796:Genes; D006147:Guanine / Q000378:metabolism; D007042:Hypoxanthines / Q000378:metabolism; D009154:Mutation; D010430:Pentosyltransferases / Q000096:biosynthesis*; D011685:Purine Nucleotides / Q000096:biosynthesis; D011683:Purine-Nucleoside Phosphorylase / Q000096:biosynthesis*; D014970:Xanthines / Q000378:metabolism
chemical_list: D007042:Hypoxanthines; D011685:Purine Nucleotides; D014970:Xanthines; D006147:Guanine; D010430:Pentosyltransferases; D011683:Purine-Nucleoside Phosphorylase; D000225:Adenine