ENZYMIC SYNTHESIS AND BREAKDOWN OF A PYRIMIDINE, OROTIC ACID .1. DIHYDRO-OROTIC DEHYDROGENASE
ENZYMIC SYNTHESIS AND BREAKDOWN OF A PYRIMIDINE, OROTIC ACID .1. DIHYDRO-OROTIC DEHYDROGENASE
复制标题
DOI：
10.1016/0006-3002(53)90141-3
复制
发表时间：
1953-01-01
期刊：
影响因子：
--
通讯作者：
KORNBERG, A
中科院分区：
文献类型：
--
作者：
LIEBERMAN, I;KORNBERG, A
用罗丹明酸富集培养分离到的一株厌氧土壤细菌提取物中含有一种酶，该酶被部分纯化。该酶为二氢脱氢酶，催化反应的顺序为：甲酸+DPNH+H+二氢-甲酸+DPN。酶还原的产物以结晶的形式分离出来，经元素分析和二氢麦芽酸的等量重量分析证明是正确的。暂时，它被认为是一种在C4-C5键饱和的二氢高岭酸。反应的平衡强烈地有利于甲酸的还原；二氢甲酸的氧化只有在脱除DPNH的体系的帮助下才能证明。二氢玫瑰花酸在支持保加利亚乳杆菌09的生长方面与玫瑰花酸一样有效，保加利亚乳杆菌09是一种利用玫瑰花酸和尿苷琥珀酸合成核酸嘧啶的生物。马来酸与尿素的融合产物具有二氢鸟粪酸的元素组成，是二氢鸟粪酸脱氢酶的惰性产物，是保加利亚乳杆菌09的生长因子。根据u-v，它可进一步与酶促来源的二氢罗丹明酸区分开来。光谱和化学性质。讨论了二氢嘧啶类化合物在嘧啶代谢中的意义。
Extracts of an anaerobic soil bacterium isolated by enrichment culture on orotic acid contain an enzyme which was purified partially. The enzyme, dihydro-orotic dehydrogenase, catalyzes the reaction: orotate + DPNH + H+dihydro-orotate + DPN. The product of the enzymic reduction of orotic acid was isolated in crystalline form and was shown to have the correct elementary analysis and equivalent wt. for dihydro-orotic acid. Provisionally, it is considered to be a dihydro-orotic acid saturated at the C4-C5 bond. The equilibrium of the reaction strongly favors orotic acid reduction; oxidation of dihydro-orotic acid is demonstrable only with the aid of a system which removes DPNH. Dihydro-orotic acid is as effective as orotic acid in supporting growth of Lactobacillus bulgaricus 09, an organism which utilizes orotic acid and ureidosuccinic acid for synthesis of nucleic acid pyrimidines. The fusion product of maleic acid and urea, which has the elementary composition of dihydro-orotic acid, is inert with dihydro-orotic dehydrogenase and as a growth factor for L. bulgaricus 09. It is distinguishable further from dihydro-orotic acid of enzymatic origin on the basis of u.-v. spectrum and chemical properties. The significance of dihydropyrimidines in pyrimidine metabolism is discussed.