60Coγ射线对从鸡胚脑分离的缬氨酰-tRNA合成酶的影响。
Effect of 60Co gamma radiation on the valyl-tRNA synthetase isolated from chick embryo brain.
作者信息
Bölöni E, Szabó L D
出版信息
Int J Radiat Biol Relat Stud Phys Chem Med. 1978 Oct;34(4):329-36. doi: 10.1080/09553007814550961.
The effect of 60Co gamma irradiation on the activity of valyl-tRNA synthetase isolated from chick embryo brain was studied. The enzyme activity exponentially decreased in the dose range 10--200 krad. The first step of the enzyme action, i.e. the amino acid activation, was found to be less sensitive to irradiation than the whole reaction, the formation of valyl-tRNA, 2-Mercapto ethanol and/or glycerol had a significant radioprotective effect. The lesion caused by radiation in the enzyme was also influenced by its concentration during exposure (dilution effect). According to gel-electrophoretic experiments, no chain rupture occurred in the enzyme molecule. Not even a change in Km was observed; however, the maximum velocity of the reaction was found to decrease with increasing radiation dose.
研究了(^{60}Co)γ射线辐照对从鸡胚脑中分离的缬氨酰 - tRNA合成酶活性的影响。在(10 - 200)千拉德的剂量范围内，酶活性呈指数下降。发现酶作用的第一步，即氨基酸活化，对辐照的敏感性低于整个反应，缬氨酰 - tRNA的形成，2 - 巯基乙醇和/或甘油具有显著的辐射防护作用。辐照对酶造成的损伤也受其暴露期间浓度的影响（稀释效应）。根据凝胶电泳实验，酶分子中未发生链断裂。甚至未观察到(Km)的变化；然而，发现反应的最大速度随着辐射剂量的增加而降低。
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