【摘要】 报道了小牛胸腺ＤＮＡ钠盐与Ｙ３＋、Ｓｍ３＋、Ｌａ３＋离子分别在摩尔比为１∶０．５，１∶１，１∶２，１∶４时，熔解温度ｔｍ的变化．实验结果表明，此３种稀土离子对ＤＮＡ的ｔｍ影响表现为：在低浓度时ｔｍ变化不大；当摩尔比为２．０以上时，ｔｍ明显降低，３种离子使小牛胸腺ＤＮＡ的ｔｍ下降的趋势为：Ｓｍ３＋＞Ｌａ３＋＞Ｙ３＋．此外，还发现Ｌａ３＋对ＤＮＡ的双螺旋结构的影响与其它稀土离子相异更多还原

【Abstract】 The variations of the melting temperature( t m) of Calf thymus DNA are discussed when Y 3+ ,Sm 3+ ,La +3 /DNA(P) molar rations (r ) are 1/2,1/1,2/1,4/1 respectively. At low molar rations of metal ions /DNA(P), t m changed a little; at high molar rations of M 3+ /DNA(P) ( r )2/1, t m decreased obviously and the trend of the fall was:Sm 3+ >La +3 > Y 3+ . In addition, we observed that the effect of trivalent Lathanum ion on DNA double helicity was different from that of others ions.更多还原