Gero A M, O'Sullivan W J
Biochem Med. 1985 Aug;34(1):70-82. doi: 10.1016/0006-2944(85)90063-8.
Human spleen dihydroorotate dehydrogenase is associated with the mitochondrial membrane and is linked to the respiratory chain via ubiquinone. The enzyme activity was unaffected by pyridine nucleotides. The product of the reaction, orotate, was a potent inhibitor. However, a range of other naturally occurring pyrimidines or purines had no significant effect on the activity. No evidence for the involvement of a complexed metal ion or for an active sulfhydryl group was obtained. Purification of the enzyme was achieved by preparation of an acetone powder and extraction with Triton X-100, followed by preparative polyacrylamide gel electrophoresis. Activity was observed by the addition of the artificial electron acceptors, ubiquinone 50 or PMS. Purification resulted in alteration of the pH optimum and of other kinetic characteristics. Two molecular-weight species, of molecular weight 88,000 and 98,000, were consistently observed. The properties of the human spleen enzyme were similar in principle to those for the rat liver enzyme. Differences in the mode of linkage to the respiratory chain for the mitochondrially bound enzyme, and in the characteristics of the purified enzyme, were observed.
人脾脏二氢乳清酸脱氢酶与线粒体膜相关联，并通过泛醌与呼吸链相连。该酶活性不受吡啶核苷酸影响。反应产物乳清酸是一种强效抑制剂。然而，一系列其他天然存在的嘧啶或嘌呤对该活性没有显著影响。未获得有关复合金属离子参与或活性巯基参与的证据。通过制备丙酮粉并用Triton X - 100萃取，随后进行制备性聚丙烯酰胺凝胶电泳实现了该酶的纯化。通过添加人工电子受体泛醌50或吩嗪硫酸甲酯观察到活性。纯化导致最适pH值和其他动力学特性发生改变。始终观察到两种分子量分别为88,000和98,000的分子物种。人脾脏酶的性质原则上与大鼠肝脏酶的性质相似。观察到线粒体结合酶与呼吸链的连接方式以及纯化酶的特性存在差异。
