黄曲霉素B_1与tRNA的结合作用

Binding action of aflatoxin B_1 to tRNA

本文应用肝微粒体系统在体外激活黄曲霉素B_1(AFB_1), 研究了其与tRNA的结合作用,结果表明AFB_1能与tRNA结合形成加成物,tRNA与AFB_1不同的结合量呈直线关系,光谱分析显示AFB_1-tRNA加成物的最大吸收峰为339nm,而tRNA的λ_(max)为260nm,AFB_1的λ_(max)为360nm,本文研究结果表明AFB_1-tRNA加成物对tRNA与氨基酸结合活性有明显的抑制作用。

Aflatoxin B1(AFB1)is a potent hepatic carcinogen and also a strong inhibitor for liver nuclear RNA synthesis.In this paper,the AFB1 activated in vitro with liver microsome system had been applied to study the binding action of AFB1 to tRNA.Linear correlation existed in various binding amounts of AFB1 to tRNA.The UV spectrophotometric measurement and absorption spectrum were studied and revealed the peak with maxima(λmax)of AFB1-tRNA adducts at 339 nm,while λmax of tRNA was at 260 nm and that of AFB1 at 360 nm.The experimental results showed that AFB1 was capable of bind-ing with tRNA to form an adduct.The inhibitory action of AFB1 tRNA adduct on the amino acid acceptor activity of tRNA was also studied.The inhibition rates were 66.7%(for lysine),48.7%(arginine),46.3%(leucine),35.5%(glycine)and 6.3%(valine),respectively.These results imply that AFB1 tRNA adduct intervene biosynthesis of protein and cellular metabolism at translation level.