Iwasaki K, Motoyoshi K, Nagata S, Kaziro Y
J Biol Chem. 1976 Mar 25;251(6):1843-5.
Eukaryotic polypeptide elongation factor 1 (EF-1) from pig liver has been resolved into two complementary factors, EF-1alpha and EF-1beta (Iwasaki, K., Mizumoto, K., Tanka, M., and Kaziro, Y. (1973) J. Biochem. (Tokyo) 74, 849). This paper describes the procedures for purification of EF-1beta and some properties of the purified factor. The purification method includes an aqueous two-phase separation technique, a treatment of the crude factor with sodium cholate and two successive column chromatographies on diethyl-aminoethyl-Sephadex A-50. By this method, EF-1beta was purified about 50-fold starting from the material obtained after two-phase separation followed by ammonium sulfate fractionation with a recovery of 20%. The purified EF-1beta appeared homogeneous, having a molecular weight of about 90,000. It consisted of two unequal subunits of the molecular weights of 55,000 and 30,000. It stimulates polymerization of phenylalanine dependent on poly(U) in the presence of both EF-1alpha and EF-2, as well as the EF-1alpha-dependent binding of phenylalanyl-tRNA to ribosomes in the presence of GTP. However, it had no effect on the stoichiometric binding of phenylalanyl-tRNA to ribosomes dependent on EF-1alpha in the presence of guanyl-5'-yl methylenediphosphonate. These results indicate that the function of EF-1beta is to stimulate the recycling of EF-1alpha.
猪肝中的真核生物多肽延伸因子1（EF-1）已被分解为两个互补因子，即EF-1α和EF-1β（岩崎，K.，水本，K.，丹贺，M.，和柿iro，Y.（1973年）《生物化学杂志》（东京）74，849）。本文描述了EF-1β的纯化程序以及纯化因子的一些特性。纯化方法包括水相两相分离技术、用胆酸钠处理粗因子以及在二乙氨基乙基-葡聚糖A-50上进行两次连续柱色谱。通过这种方法，从两相分离后再经硫酸铵分级分离得到的材料开始，EF-1β被纯化了约50倍，回收率为20%。纯化的EF-1β看起来是均一的，分子量约为90,000。它由分子量分别为55,000和30,000的两个不相等的亚基组成。在EF-1α和EF-2存在的情况下，它能刺激依赖于聚（U）的苯丙氨酸聚合，以及在GTP存在的情况下，刺激苯丙氨酰-tRNA与核糖体的EF-1α依赖性结合。然而，在存在鸟苷-5'-亚甲基二磷酸的情况下，它对依赖于EF-1α的苯丙氨酰-tRNA与核糖体的化学计量结合没有影响。这些结果表明EF-1β的功能是刺激EF-1α的循环利用。
