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镉是一种致癌物质。动物给予锌和镁能抑制镉的致癌作用,而给予钙则无此作用。然而金属的致癌机制迄今尚未清楚。为此,作者在试管内研究了Cd与DNA的结合以及Ca、Mg和Zn对Cd结合的影响。用100μg纯的小牛胸腺DNA(于2mM三羟甲基甲烷-盐酸中,pH 7.4,0.1 mg/ml)同各种浓度的放射性氯化镉(0.1～250μM,含2.5μci如~(109)Cd/μmol Cd)混合。混合物分别在加入和不加入Ca(80 μzM)、Mg(70 μM)、Zn(40 μM)的情况下在24℃孵化1小时后,通过凝胶过滤分离
Cadmium is a carcinogen. Zinc and magnesium were given to animals for their ability to inhibit the carcinogenic effects of cadmium, whereas calcium did not. However, the mechanism of carcinogenesis of metals has not yet been clarified. To this end, the authors studied the binding of Cd to DNA and the effects of Ca, Mg and Zn on Cd binding in vitro. Cells were treated with 100 μg of purified calf thymus DNA (pH 7.4, 0.1 mg / ml in 2 mM trimethylolpropane-HCl) with various concentrations of radioactive cadmium chloride (0.1-250 μM, Cd / μmol Cd). The mixture was incubated at 24 ° C for 1 hour with and without addition of Ca (80 μM), Mg (70 μM), Zn (40 μM), respectively, and separated by gel filtration