Legris A J, Tsai C S
Can J Biochem. 1975 May;53(5):527-35. doi: 10.1139/o75-073.
Malate dehydrogenase of wheat germ exists in multiple molecular forms (isozymes). Comparisons of some physical properties such as Stoke's radii, sedimentation constants, electrophoretic mobilities on polyacrylamide gel, chromatographic behaviors on DEAE-cellulose, stabilities to heat and iodacetamide inactivation, as well as kinetic parameters were described. When all these properties are considered together, at least five isozymes were found to associate with cytoplasm, mitochondria, glyoxysomes and proplastids of wheat germ. Wheat germ malate dehydrogenases are specific for the reduction of oxaloacetate and its monoesters. At least one carboxylic group of oxaloacetate must be free, in order to exhibit substrate activity, and maximum binding of oxaloacetate is achieved when both carboxylic groups are free. Soluble malate dehydrogenase and organelle-associated malate dehydrogenase can be differentiated readily in that the former can not utilize 4-ethyl oxaloaceode of ATP inhibition.
小麦胚芽苹果酸脱氢酶以多种分子形式（同工酶）存在。文中描述了一些物理性质的比较，如斯托克斯半径、沉降常数、在聚丙烯酰胺凝胶上的电泳迁移率、在DEAE - 纤维素上的色谱行为、对热和碘乙酰胺失活的稳定性以及动力学参数。综合考虑所有这些性质时，发现至少有五种同工酶与小麦胚芽的细胞质、线粒体、乙醛酸循环体和前质体相关。小麦胚芽苹果酸脱氢酶对草酰乙酸及其单酯的还原具有特异性。为了表现出底物活性，草酰乙酸至少有一个羧基必须是游离的，当两个羧基都游离时，草酰乙酸的结合达到最大值。可溶性苹果酸脱氢酶和与细胞器相关的苹果酸脱氢酶很容易区分，因为前者不能利用4 - 乙基草酰乙酸进行ATP抑制。
