Jakubowski H
Biochim Biophys Acta. 1978 Apr 27;518(2):345-50. doi: 10.1016/0005-2787(78)90191-0.
The extent of esterification of [14C] leucine into Escherichia coli B tRNALeu apparently depends on the concentration of leucyl-tRNA synthetase. The effect is more pronounced at pH 9.0 than at pH 7.4. When reciprocals of leucyl-tRNA concentration at plateau [aa-tRNA]-1 are plotted against reciprocals of initial velocities vo-1 of aminoacylations a straight line is obtained with a slope equal to the rate constant of non-enzymatic deacylation of leucyl-tRNA. Factors which change the stability of leucyl-tRNA, e.g. pH and temperature, also change the shape of the function [aa-tRNA]-1 vs. vo-1. The data are consistent with the idea that the rate constant of spontaneous deacylation of aminoacyl-tRNA is the factor which accounts for the dependence of the level of aminoacylation on initial velocity of aminoacylation.
[14C]亮氨酸酯化到大肠杆菌B的tRNALeu中的程度显然取决于亮氨酰-tRNA合成酶的浓度。在pH 9.0时这种效应比在pH 7.4时更明显。当将平台期[aa-tRNA]-1时亮氨酰-tRNA浓度的倒数与氨酰化初始速度vo-1的倒数作图时，可得到一条直线，其斜率等于亮氨酰-tRNA非酶促脱酰基的速率常数。改变亮氨酰-tRNA稳定性的因素，如pH和温度，也会改变[aa-tRNA]-1与vo-1函数的形状。这些数据与以下观点一致，即氨酰-tRNA自发脱酰基的速率常数是解释氨酰化水平对氨酰化初始速度依赖性的因素。
