铕（III）与酵母乙醇脱氢酶的相互作用。

Interaction of Eu3+ with yeast alcohol dehydrogenase.

作者信息

Zhang Y X, Duan C L, Zhou H M

机构信息

Department of Chemistry, Capital University of Medical Sciences, Beijing, China.

出版信息

J Protein Chem. 1999 Jan;18(1):97-101. doi: 10.1023/a:1020607818690.

DOI:10.1023/a:1020607818690

PMID:10071934

Abstract

The activity of yeast alcohol dehydrogenase is markedly enhanced by Eu3+ ions. At pH 7.0 two binding constants for Eu3+, 1.0x10(-2) and 2.0x10(-3) microM, were obtained using a Scatchard plot. The presence of Zn2+ ions restricts the Eu3+ -induced increase in the activity of yeast alcohol dehydrogenase. Studies on the tryptophan fluorescence of the enzyme in the absence and presence of Eu3+ or Zn2+ ions showed that Eu3+ affects tertiary or quaternary structures, which is consistent with its activation of the enzyme. The presence of Zn2+ reverses the conformational changes caused by Eu3+. Comparison of the effects of Eu3+ with Zn2+ for apo-yeast alcohol dehydrogenase indicates that their binding sites on the protein are different.

摘要

铕离子可显著增强酵母乙醇脱氢酶的活性。在pH 7.0条件下，使用Scatchard图得到铕离子的两个结合常数，分别为1.0×10⁻²和2.0×10⁻³微摩尔。锌离子的存在会抑制铕离子诱导的酵母乙醇脱氢酶活性增加。对该酶在有无铕离子或锌离子存在时的色氨酸荧光研究表明，铕离子影响三级或四级结构，这与其对酶的激活作用一致。锌离子的存在可逆转铕离子引起的构象变化。对脱辅基酵母乙醇脱氢酶而言，铕离子与锌离子作用效果的比较表明，它们在蛋白质上的结合位点不同。