Woods R A, Roberts D G, Stein D S, Filpula D
J Gen Microbiol. 1984 Oct;130(10):2629-37. doi: 10.1099/00221287-130-10-2629.
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.
在携带编码氨甲酰磷酸核糖基转移酶(EC 2,4,2,14)的基因的ade4-su等位基因的原养型菌株中,通过选择对8-氮杂腺嘌呤具有抗性,分离出了缺乏腺嘌呤磷酸核糖基转移酶(A-PRT,EC 2,4,2,7)的酿酒酵母突变体。这些突变体是隐性的,并且定义了一个单一基因apt1。当与ade4+结合时,它们不会排泄嘌呤。突变体在粗提取物中似乎保留了一些A-PRT活性,并且基因型为ade2 apt1的菌株对腺嘌呤和次黄嘌呤都有反应。缺乏腺嘌呤氨基水解酶(EC 3,5,4,2)活性的突变体aah1和缺乏次黄嘌呤:鸟嘌呤磷酸核糖基转移酶(EC 2,4,2,8)活性的突变体hpt1,被用于合成基因型apt1 hpt1 aah+和apt1 hpt+ aah1。这些基因型菌株中A-PRT活性的缺失证实了这样的假设,即apt1突变体的残余A-PRT活性是由于腺嘌呤氨基水解酶和次黄嘌呤:鸟嘌呤磷酸核糖基转移酶协同作用的结果。