Miersch J, Logvinenko E M, Zakalsky A E, Shavlovsky G M, Reinbothe H
Biochim Biophys Acta. 1978 Oct 18;543(3):305-12. doi: 10.1016/0304-4165(78)90048-x.
In wild-type cells and some riboflavin-deficient mutants of P. guilliermondii GTP is transformed to the ribitylated intermediates 2,5-diamino-6-hydroxy-4-ribitylaminopyrimidine and 5-amino-2,6-dihydroxy-4-ribitylaminopyrimidine of the riboflavin biosynthetic path. We were able to show that these compounds were formed in vitro as well as in permeabilized cells by reactions including a reductive conversion of the product of GTP cyclohydrolase II action upon GTP. In order to analyse the pyrimidine derivates, 6,7-dimethyl-8-ribitylpterin and 6,7-dimethyl-8-ribityllumazine were synthesized by reaction of pyrimidines with diacetyl. The formation of ribitylated pyrimidines was shown to be strictly dependent on the presence of NADPH2. The data obtained indicate that the reductive step is catalyzed by a 2,5-diamino-6-hydroxy-4-ribosylaminopyrimidine-reductase. 6,7-Dimethyl-8-ribitylpterin and 6,7-dimethyl-8-ribityllumazine isolated from the incubation mixtures have been identified by chromatography and by their ultraviolet and fluorescence spectra.
在野生型细胞和季也蒙毕赤酵母的一些核黄素缺陷型突变体中，鸟苷三磷酸（GTP）被转化为核黄素生物合成途径中的核糖基化中间体2,5 - 二氨基 - 6 - 羟基 - 4 - 核糖基氨基嘧啶和5 - 氨基 - 2,6 - 二羟基 - 4 - 核糖基氨基嘧啶。我们能够证明，这些化合物在体外以及透化细胞中通过包括对GTP的鸟苷三磷酸环化水解酶II作用产物进行还原转化的反应而形成。为了分析嘧啶衍生物，通过嘧啶与二乙酰的反应合成了6,7 - 二甲基 - 8 - 核糖基蝶呤和6,7 - 二甲基 - 8 - 核糖基六氢喋啶。已证明核糖基化嘧啶的形成严格依赖于还原型辅酶II（NADPH2）的存在。所获得的数据表明，还原步骤由2,5 - 二氨基 - 6 - 羟基 - 4 - 核糖基氨基嘧啶还原酶催化。从孵育混合物中分离出的6,7 - 二甲基 - 8 - 核糖基蝶呤和6,7 - 二甲基 - 8 - 核糖基六氢喋啶已通过色谱法及其紫外和荧光光谱进行了鉴定。
