柠檬酸合酶的分子生物学研究进展

柠檬酸合酶（citrate synthase,CS）是细胞内多种重要代谢途径的关键酶。CS可催化草酰乙酸和乙酰辅酶A之间的缩合反应生成柠檬酸和辅酶A。通常革兰氏阳性细菌、古菌以及真核细胞的CS为同源二聚体,而革兰氏阴性细菌的CS为同源六聚体。根据其在细胞内的定位不同,CS可分为线粒体CS、乙醛酸循环体CS、过氧化物酶体CS。这些同工酶在能量代谢、植物脂肪的代谢、脂肪酸的氧化及细胞解毒过程中起着重要作用。不同来源的CS空间结构、催化机制和动力学性质十分相似。针对其生化特性、空间结构特点、催化机制以及分子进化等研究进展进行综述。

Advances in molecular biology of citrate synthase

Citrate synthase（CS,EC 4.1.3.7） is a Key enzyme of multiple important metabolic pathways in cells.Citrate synthase catalyzes the condensation of oxaloacetate and acetyl-coenzyme A to form citrate and Acetyl-CoA.The enzymes from Archaea,Gram-positive bacteria and eukaryotes are usually homodimers,whereas those from Gram-negative bacteria are homohexamers.According to the different locations in cells,CS can be divided into mitochondrial CS,glyoxysome CS and peroxisome CS.The isoenzymes of CS play crucial roles in energy metabolism,lipid metabolism of plants,fatty acid oxidization and detoxification of cells.The enzymes share a similar three-dimensional structure,catalytic mechanism and kinetic properties.The advances of CS in the characteristics of biochemistry and crystal structure,catalysis mechanism and molecular evolution are discussed in this paper.