粟酒裂殖酵母中嘌呤磷酸核糖转移酶的底物特异性。

The substrate specificity of purine phosphoribosyltransferases in Schizosaccharomyces pombe.

De Groodt A, Whitehead E P, Heslot H, Poirier L

Biochem J. 1971 May;122(4):415-20. doi: 10.1042/bj1220415.

Abstract

The activities of the purine phosphoribosyltransferases (EC 2.4.2.7 and 2.4.2.8) in purine-analogue-resistant mutants of Schizosaccharomyces pombe were checked. An 8-azathioxanthine-resistant mutant lacked hypoxanthine phosphoribosyltransferase, xanthine phosphoribosyltransferase and guanine phosphoribosyltransferase activities (EC 2.4.2.8) and appeared to carry a single mutation. Two 2,6-diaminopurine-resistant mutants retained these activities but lacked adenine phosphoribosyltransferase activity (EC 2.4.2.7). This evidence, together with data on purification and heat-inactivation patterns of phosphoribosyltransferase activities towards the various purines, strongly suggests that there are two phosphoribosyltransferase enzymes for purine bases in Schiz. pombe, one active with adenine, the other with hypoxanthine, xanthine and guanine. 2. Neither growth-medium supplements of purines nor mutations on genes involved in the pathway for new biosynthesis of purine have any influence on the amount of hypoxanthine-xanthine-guanine phosphoribosyltransferase produced by this organism.

摘要

检测了粟酒裂殖酵母嘌呤类似物抗性突变体中嘌呤磷酸核糖转移酶（EC 2.4.2.7和2.4.2.8）的活性。一株8-氮硫代黄嘌呤抗性突变体缺乏次黄嘌呤磷酸核糖转移酶、黄嘌呤磷酸核糖转移酶和鸟嘌呤磷酸核糖转移酶活性（EC 2.4.2.8），似乎携带单一突变。两株2,6-二氨基嘌呤抗性突变体保留了这些活性，但缺乏腺嘌呤磷酸核糖转移酶活性（EC 2.4.2.7）。这些证据，连同关于磷酸核糖转移酶对各种嘌呤活性的纯化和热失活模式的数据，有力地表明粟酒裂殖酵母中存在两种用于嘌呤碱基的磷酸核糖转移酶，一种对腺嘌呤有活性，另一种对次黄嘌呤、黄嘌呤和鸟嘌呤有活性。2. 嘌呤的生长培养基补充物或嘌呤新生物合成途径中相关基因的突变均对该生物体产生的次黄嘌呤-黄嘌呤-鸟嘌呤磷酸核糖转移酶的量没有任何影响。