Horner J, Champney W S, Samuels R
Department of Biochemistry, University of Illinois, Urbana 61801.
Int J Parasitol. 1991 Apr;21(2):275-7. doi: 10.1016/0020-7519(91)90023-z.
This study has investigated the characteristics of a leucine aminoacyl transfer RNA synthetase enzyme from Tritrichomonas augusta. Differential centrifugation and DEAE-cellulose column chromatography were used for partial enzyme purification. The column purification increased the synthetase activity 125-fold over the unfractionated cell extract. The conditions for maximum [3H] leucine charging were 37 degrees C for 20 min, with protein at 180 micrograms ml-1 using yeast leucine tRNA as an acceptor. The optimal reaction conditions were 14 mM-Mg acetate, 3 mM-ATP, 3 mM-spermidine and 5.5 mM-putrescine. Acceptor activity with T. augusta transfer RNA was 8-fold higher than with yeast transfer RNA and 25-fold higher than with Escherichia coli transfer RNA. The partially purified enzyme fraction had comparable changing activities for both leucine and valine.
本研究调查了奥氏三毛滴虫亮氨酸氨酰基转移RNA合成酶的特性。采用差速离心和DEAE-纤维素柱色谱法对该酶进行部分纯化。柱纯化使合成酶活性比未分级的细胞提取物提高了125倍。以酵母亮氨酸tRNA为受体时，最大[3H]亮氨酸负载的条件为37℃孵育20分钟，蛋白质浓度为180微克/毫升。最佳反应条件为14 mM-醋酸镁、3 mM-ATP、3 mM-亚精胺和5.5 mM-腐胺。奥氏三毛滴虫转移RNA的受体活性比酵母转移RNA高8倍，比大肠杆菌转移RNA高25倍。部分纯化的酶组分对亮氨酸和缬氨酸具有相当的负载活性。
