Söhling B, Gottschalk G
Institut für Mikrobiologie, Georg-August-Universität Göttingen, Federal Republic of Germany.
Eur J Biochem. 1993 Feb 15;212(1):121-7. doi: 10.1111/j.1432-1033.1993.tb17641.x.
Cell extracts of Clostridium kluyveri, grown on ethanol plus succinate contained a succinyl-CoA:CoA transferase (0.28 U/mg), a coenzyme-A-dependent succinate-semialdehyde dehydrogenase (0.73 U/mg) and a NAD(+)-dependent 4-hydroxybutyrate dehydrogenase (0.25 U/mg). The semialdehyde dehydrogenase, which catalyzed the NADPH-dependent reduction of succinyl-CoA to succinate semialdehyde, was purified 59-fold to homogeneity. A molecular mass of 115000 Da was determined for the native enzyme; SDS/PAGE revealed one protein band at 55,000, indicating that the active form is a dimer. The enzyme was highly specific for succinyl-CoA and succinate semialdehyde. The pH optimum was 7.0 for the reduction of succinyl-CoA, and 8.5 for the reverse reaction. Km values were determined for both the forward and reverse directions. The kinetic data suggest a ping-pong mechanism.
在乙醇加琥珀酸上生长的克氏梭菌细胞提取物含有一种琥珀酰辅酶A：辅酶A转移酶（0.28 U/mg）、一种依赖辅酶A的琥珀酸半醛脱氢酶（0.73 U/mg）和一种依赖NAD⁺的4-羟基丁酸脱氢酶（0.25 U/mg）。催化NADPH依赖的琥珀酰辅酶A还原为琥珀酸半醛的半醛脱氢酶被纯化了59倍达到同质。测定该天然酶的分子量为115000 Da；SDS/PAGE显示在55000处有一条蛋白带，表明活性形式是二聚体。该酶对琥珀酰辅酶A和琥珀酸半醛具有高度特异性。还原琥珀酰辅酶A的最适pH为7.0，反向反应的最适pH为8.5。测定了正向和反向反应的Km值。动力学数据表明是乒乓机制。
