当前位置: 首页 > 文章 > 镧离子对肉牛胰腺核糖核酸酶活性的影响及作用机制 中国兽医学报 2004,24 (1) 94-96
Position: Home > Articles > Effect of Lanthanum Ions on RNase Activity from Bovine Pancreas Chinese Journal of Veterinary Science 2004,24 (1) 94-96

镧离子对肉牛胰腺核糖核酸酶活性的影响及作用机制

作  者:
王立克;洪法水
单  位:
苏州大学生命科学院;安徽技术师范学院
关键词:
核糖核酸酶;镧离子;酶活性;结合位点
摘  要:
在肉牛胰腺核糖核酸酶 (RNase)介质中加入 L a3+ ,研究了其对 RNase活性的影响及作用机制。结果表明 ,适当浓度的 L a3+ 对酶活性有激活作用 ,高浓度则严重抑制酶活性。竞争实验表明 ,高浓度下 ,L a3+ 可置换出 RNase中的Ca2 + 。荧光滴定表明 ,在 1个 RNase分子上结合有 2 .5个 L a3+ ,其低亲和性结合位点上的结合常数 ksv=1.33× 10 8L· mol- 1。由于高浓度下 L a3+对核糖核酸酶中 Ca2 +的竞争取代 ,因而可能导致酶的构象改变 ,使酶失去活性
译  名:
Effect of Lanthanum Ions on RNase Activity from Bovine Pancreas
作  者:
WANG Li-ke~1,HONG Fa-shui~2(1.Anhui Technical Teachers College,Fengyang,Anhui 233100,China; 2.College of Life Sciences,Suzhou University,Suzhou,Jiangsu 215006,China)
关键词:
RNase;Lanthanum ions;enzyme activity;binding site
摘  要:
The activity of RNase from bovine pancreas was enhanced under the treatment by Ca~(2+),La~(3+) at the low concentration(10-40 or 10-60 μmol/L),but was inhibited by La~(3+) at the high concentration(over 50 μmol/L).The equilibrium dialysis demonstrated that RNase might have one Ca~(2+)-binding site.La~(3+) at high concentration could competitively displace Ca~(2+) from RNase.The fluorescence titration showed that one molecule of RNase has 2.5 binding sites for La~(3+),with the association constant ksv for low-affinity La~(3+)-binding site of 1.33×10~8 L·mol~(-1).The paper speculated that the structure of RNase might be greatly damaged by La~(3+) at high concentration,and its activity was decreased.

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