Department of Biochemistry, University of California at Riverside, Riverside, California 92502.
Plant Physiol. 1972 Feb;49(2):117-23. doi: 10.1104/pp.49.2.117.
Malate dehydrogenase isolated from leaves of the cotton plant (Gossypium hirsutum L.) appears in the form of several isoenzymes. Four of the isoenzymes found in cotton leaf extracts appear to be charge isomers with a molecular weight of approximately 60,000. A fifth malate dehydrogenase isoenzyme found in leaf extracts has a molecular weight of approximately 500,000. Under appropriate conditions it is possible to form this high molecular weight isoenzyme from at least one of the smaller isoenzymes. In addition, malate dehydrogenase isoenzymes of approximately 700,000 and 130,000 molecular weight have been observed under some conditions, although these isoenzymes do not appear in the crude cotton leaf preparations. The relationship of this heterogeneity with respect to size and to the discrepancies in the number and size of malate dehydrogenase isoenzymes reported from plant tissues may be significant.
从棉花叶片（Gossypium hirsutum L.）中分离出的苹果酸脱氢酶以几种同工酶的形式存在。在棉叶提取物中发现的四种同工酶似乎是带有约 60,000 分子量的电荷异构体。在叶片提取物中发现的第五种苹果酸脱氢酶同工酶的分子量约为 500,000。在适当的条件下，至少有一种较小的同工酶可以形成这种高分子量同工酶。此外，在某些条件下还观察到分子量约为 700,000 和 130,000 的苹果酸脱氢酶同工酶，尽管这些同工酶不在粗制棉花叶片制剂中出现。这种大小和数量以及苹果酸脱氢酶同工酶大小的差异的异质性与植物组织中的报告可能具有重要意义。
