欧洲醋杆菌柠檬酸合酶的纯化及性质

Purification and properties of citrate synthase from Acetobacter europaeus.

作者信息

Sievers M, Stöckli M, Teuber M

机构信息

Food Microbiology, ETH-Zürich, Switzerland.

出版信息

FEMS Microbiol Lett. 1997 Jan 1;146(1):53-8. doi: 10.1111/j.1574-6968.1997.tb10170.x.

DOI:10.1111/j.1574-6968.1997.tb10170.x

PMID:8997706

Abstract

Citrate synthase (EC 4.1.3.7) was purified from the acidophilic bacterium Acetobacter europaeus to electrophoretic homogeneity. The specific activity was 228 units/mg of protein during the exponential ethanol-oxidation growth phase. The enzyme has a molecular mass of 280 kDa and is a hexamer with a subunit size of 46 kDa. The apparent K(m) values were 20 microM for oxaloacetate and 51 microM for acetyl-CoA. Unlike citrate synthase from other Gram-negative bacteria, the activity of the enzyme was inhibited by ATP, slightly enhanced by ADP and not effected by NADH. Acetate caused activation of the enzyme. The pH optimum on the citrate synthase activity in vitro was 8.1. The amino-terminal amino acid sequence of the purified enzyme was ENGKSATISLNGKDVALPVL.

摘要

柠檬酸合酶（EC 4.1.3.7）从嗜酸细菌欧洲醋杆菌中纯化至电泳纯。在乙醇氧化指数生长期，比活性为228单位/毫克蛋白。该酶分子量为280 kDa，是一个六聚体，亚基大小为46 kDa。草酰乙酸的表观K(m)值为20 μM，乙酰辅酶A的表观K(m)值为51 μM。与其他革兰氏阴性菌的柠檬酸合酶不同，该酶的活性受ATP抑制，受ADP轻微增强，不受NADH影响。乙酸可使该酶激活。体外柠檬酸合酶活性的最适pH为8.1。纯化酶的氨基末端氨基酸序列为ENGKSATISLNGKDVALPVL。