| Pb2+对胰蛋白酶活性影响的作用机理研究 |
| Study of Pb2+ on the Mechanism of Trypsin Activity |
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| 摘要: 在胰蛋白酶介质中加入Pb2+， 研究其对胰蛋白酶活性影响的作用机理。结果表明低浓度的Pb2+对酶有激活作用，高浓度则严重抑制酶活性。在高浓度下，Pb2+能完全竞争出胰蛋白酶中的Ca2+而结合到了胰蛋白酶上，其EXAFS的测试表明Pb2+与多肽链氨基酸残基上的氨基或羧基发生了配位，配位数为2，Pb-N或Pb-O键长为0.241nm。圆二色谱测试表明高浓度的Pb2+结合使胰蛋白酶的二级结构被破坏，α-螺旋含量、β-转角及无规则卷曲下降，β-折叠增加，因而使酶失去活性。 |
| 关键词: 胰蛋白酶 Pb2+ 酶活性 EXAFS 二级结构 |
| 基金项目: |
| Abstract: The activity of trypsin from bovine pancreas was enhanced under the treatment by Pb2+ at low concentration (0.5～3μmol·L-1)， but was inhibited by Pb2+ at high concentration (3μmol·L-1 above). Pb2+ at high con-centration could competitively displace Ca2+ from trypsin. The EXAFS demonstrated that Pb2+ bound to polypeptide chain of trypsin， coordination atom was nitrogen or oxygen， its coordination number was 2 and Pb-N (or O) bond length was 0.241nm. The secondary structure of trypsin was greatly changed by Pb2+ at high concentration， e.g. α-helix， β-turn and Random coil contents decreased and β-sheet increased. It suggested that Pb2+ bound result in trypsin conformational changed， and enzyme activity decreased. |
| Keywords: trypsin lead ion enzyme activity EXAFS secondary structure |
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| 洪法水,王玲,吴康,王雪峰,刘超,陶冶.Pb2+对胰蛋白酶活性影响的作用机理研究[J].无机化学学报,2003,19(2):129-132. |
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