Adenine phosphoribosyltransferase mutants in Saccharomyces cerevisiae.
Mutants of Saccharomyces cerevisiae deficient in adenine phosphoribosyltransferase (A-PRT, EC 2,4,2,7) have been isolated following selection for resistance to 8-azaadenine in a prototrophic strain carrying the ade4-su allele of the gene coding for amidophosphoribosyltransferase (EC 2,4,2,14). The mutants were recessive and defined a single gene, apt1. They did not excrete purine when combined with ade4+. The mutants appeared to retain some A-PRT activity in crude extracts, and strains of the genotype ade2 apt1 responded to both adenine and hypoxanthine. Mutants deficient in adenine aminohydrolase (EC 3,5,4,2) activity, aah1, and hypoxanthine:guanine phosphoribosyltransferase (EC 2,4,2,8) activity, hpt1, were used to synthesize the genotypes apt1 hpt1 aah+ and apt1 hpt+ aah1. The absence of A-PRT activity in strains with these genotypes confirmed the hypothesis that the residual A-PRT activity of apt1 mutants was due to adenine aminohydrolase and hypoxanthine:guanine phosphoribosyltransferase acting in concert.
D000228:Adenine Phosphoribosyltransferase / Q000378:metabolism*; D000483:Alleles; D000582:Amidophosphoribosyltransferase / Q000235:genetics; D000619:Aminohydrolases / Q000378:metabolism; D004586:Electrophoresis; D005838:Genotype; D007041:Hypoxanthine Phosphoribosyltransferase / Q000378:metabolism; D009154:Mutation; D010430:Pentosyltransferases / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000201:enzymology / Q000235:genetics*
D010430:Pentosyltransferases; D000582:Amidophosphoribosyltransferase; D000228:Adenine Phosphoribosyltransferase; D007041:Hypoxanthine Phosphoribosyltransferase; D000619:Aminohydrolases; C018774:adenine deaminase