扩环酶的研究进展及其应用前景

Progress in Expandase and Its Prospects of Application

扩环酶，也叫脱乙酰氧基头孢菌素Ｃ合成酶，催化青霉素Ｎ 扩环生成脱乙酰氧基头孢菌素Ｃ，是头孢菌素生物合成中的关键酶。在真菌中它是一个双功能酶，同时具有扩环酶和羟化酶的活性；而在细菌中扩环和羟化却是由两个独立的酶来承担的。近年来，扩环酶被纯化成均一蛋白，有关它的性质、分子结构以及基因结构等方面的研究都取得了飞速发展，并不断地应用基因工程的技术探索其在抗生素生产上的应用。

Expandase,also referred to as deacetoxycephalosproin C sysnthetase,which catalyzes ring expansion of penicillin N to deacetoxycephalosporin C,is a rate\|limiting enzyme in the biosyntheis of cephalosporins.In fungus,expandase is a bifunctional enzyme and the expandase activity is always phaysically associated with DAOC hydroxylase activity,wherease in the case of bacteria, the expandase and hydroxylase activities are clearly spearated. Recent years,expansase has been purified to near homogeneity.And it has made rapid progress in the studies on expandase's biologial properties, structure of molecular and gene and so on. People have been continuously finding ways to apply these knowledge to the production of antibiotecs by the technology of genetic engineering.\;