Crystallization and partial characterization of prenyltransferase from avian liver.
Crystallization and partial characterization of prenyltransferase from avian liver.
复制标题
禽类肝脏异戊二烯基转移酶的结晶和部分表征。
作者：
B. C. Reed;H. Rilling
从鸡肝中获得了稳定结晶的戊二烯转移酶(EC2.5.1.1)。经pH 8.4的聚丙烯酰胺凝胶电泳法和含有十二烷基硫酸钠的凝胶电泳法测定，该酶为均一酶。结晶酶的电聚焦产生一个等电点为5.72的单一尖锐的蛋白质峰。该蛋白质是一种分子量为86,000的二聚体，其亚基在十二烷基硫酸钠中不能被凝胶电泳所分解。异戊烯基焦磷酸酯和香叶基焦磷酸酯的米氏常数均为0.5um，比酵母或猪肝中的异戊烯基焦磷酸转移酶的米氏常数低3-20倍(Eberhardt，N.，and Ring，H.C.(1974)，J.Biol)。化学。(印刷中)；Dorsey，J.K.，Dorsey，J.A.和Porter，J.W.(1966)，J.Biol。化学。2415353；Holloway，P.W.和Popjak，G.(1967)，Biochem。J.104，57)。该酶主要由二甲基烯丙基或香叶基焦磷酸酯合成法尼基焦磷酸盐，但在一定条件下也会生成一些香叶基焦磷酸酯。这是首次制备稳定的甾醇和萜类生物合成结晶酶。
Prenyltransferase (EC 2.5.1.1) has been obtained from chicken liver in a stable crystalline form. The enzyme has been shown to be homogeneous by polyacrylamide gel electrophoresis at pH 8.4, and by electrophoresis in sodium dodecyl sulfate containing gels. Electrofocusing of the crystalline enzyme results in a single sharp protein peak with a pI of 5.72. The protein is a dimer of molecular weight 86,000 whose subunits were not resolved by gel electrophoresis in sodium dodecyl sulfate. Michaelis constants of 0.5 muM for both isopentenyl pyrophosphate and geranyl pyrophosphate are 3-20-fold lower than those found for prenyltransferase from yeast or pig liver (Eberhardt, N., and Rilling, H. C. (1974), J. Biol. Chem. (in press); Dorsey, J. K., Dorsey, J. A., and Porter, J. W. (1966), J. Biol. Chem. 241, 5353; Holloway, P. W., and Popjak, G. (1967), Biochem. J. 104, 57). The enzyme primarily synthesizes farnesyl pyrophosphosphate from dimethylallyl or geranyl pyrophosphate although some geranylgeranyl pyrophosphate is formed under certain conditons. This is the first preparation of a stable crystalline enzyme of sterol and terpene biosynthesis.