丙酸杆菌苹果酸脱氢酶与哺乳动物可溶性及线粒体同工酶的比较。

A comparison of the malate dehydrogenase of the propionic acid bacteria with the mammalian soluble and mitochondrial isoenzymes.

Allen S H, Feldman H M

Department of Biochemistry, Albany Medical College, NY 12208.

Comp Biochem Physiol B. 1978;60(3):287-93. doi: 10.1016/0305-0491(78)90103-7.

Abstract

Like the malate dehydrogenases of eucaryotic cells, the Propionibacterium shermanii enzyme is a dimer consisting of two 35,000 molecular weight subunits. 2. In electrophoretic behavior, resistance to substrate inhibition and stability to heating and dilution the P. shermanii MDH is more similar to the s-MDH than to the m-MDH of pig heart. 3. The P. shermanii MDH has a high turnover number (ca. 140,000) as well as Km values for both L-malate and oxalacetate which are four times higher than the mammalian isoenzymes. 4. A coupled assay for MDH using the malate-lactate transhydrogenase and diaphorase is described in which both substrates, L-malate and NAD, are regenerated.

摘要

与真核细胞的苹果酸脱氢酶一样，谢氏丙酸杆菌的这种酶是一种二聚体，由两个分子量为35,000的亚基组成。2. 在电泳行为、对底物抑制的抗性以及对加热和稀释的稳定性方面，谢氏丙酸杆菌苹果酸脱氢酶与猪心的可溶性苹果酸脱氢酶（s-MDH）比与线粒体苹果酸脱氢酶（m-MDH）更为相似。3. 谢氏丙酸杆菌苹果酸脱氢酶具有较高的转换数（约140,000），并且L-苹果酸和草酰乙酸的米氏常数（Km）值比哺乳动物同工酶高四倍。4. 描述了一种使用苹果酸-乳酸转氢酶和黄递酶对苹果酸脱氢酶进行的偶联测定法，其中L-苹果酸和NAD这两种底物都能再生。