Comparison of the enzymatic behavior of high molecular weight and free lysyl-tRNA synthetase from rat liver: kinetic analysis of lysylation of tRNA.
Comparison of the enzymatic behavior of high molecular weight and free lysyl-tRNA synthetase from rat liver: kinetic analysis of lysylation of tRNA.
复制标题
大鼠肝脏高分子量和游离赖氨酰-tRNA 合成酶的酶行为比较：tRNA 赖氨酰化的动力学分析。
DOI：
10.1016/0003-9861(86)90017-2
复制
发表时间：
1986
影响因子：
3.9
通讯作者：
Yang,DC
中科院分区：
文献类型：
--
作者：
Wahab,SZ;Yang,DC
赖氨酰-tRNA合成酶在大鼠肝脏中以高分子量形式存在。高分子量赖氨酰-tRNA合成酶先前已被证明作为氨酰-tRNA合成酶的多酶复合物存在。多酶复合物可以通过疏水相互作用色谱法解离，并产生完全活性的游离赖氨酰-tRNA合成酶。发现游离形式在裂解中的活性是复合形式的两倍。系统地进行了高纯度的游离赖氨酰-tRNA合成酶和18 S合成酶复合物的赖氨酰化反应的双底物和产物抑制动力学。令人惊讶的是，这两种酶形式在相同条件下在双底物和产物抑制动力学中表现出明显不同的动力学模式。18 S合成酶复合物的动力学模式与有序的双单双乒乓机制一致，而游离赖氨酰-tRNA合成酶的结果不一致。我们的结论是赖氨酰-tRNA合成酶的四级结构以外的蛋白质的结构组织可能会改变酶的行为。
Lysyl-tRNA synthetase occurs in the high molecular weight form in rat liver. The high molecular weight lysyl-tRNA synthetase has been previously demonstrated to exist as multienzyme complexes of aminoacyl-tRNA synthetases. The multienzyme complexes can be dissociated by hydrophobic interaction chromatography and yield fully active, free lysyl-tRNA synthetase. The free form is found to be twice as active as the complexed form in lysylation. Bisubstrate and product inhibition kinetics of lysylation are systematically carried out for highly purified free lysyl-tRNA synthetase and the 18 S synthetase complex. Surprisingly, the two enzyme forms exhibit distinctly different kinetic patterns in bisubstrate and product inhibition kinetics under identical conditions. The 18 S synthetase complex shows kinetic patterns consistent with an ordered bi uni uni bi ping pong mechanism, while the results of free lysyl-tRNA synthetase do not. We conclude that structural organization of lysyl-tRNA synthetase beyond quaternary structure of proteins may alter the enzyme behavior.