Ligand substitution reactions of metallothioneins with EDTA and apo-carbonic anhydrase.
Ligand substitution reactions of metallothioneins with EDTA and apo-carbonic anhydrase.
复制标题
金属硫蛋白与 EDTA 和脱辅基碳酸酐酶的配体取代反应。
DOI：
--
复制
发表时间：
1980
影响因子：
11.1
通讯作者：
D. Petering
中科院分区：
文献类型：
--
作者：
LI TA;A. Kraker;C. Shaw;D. Petering
研究了Zn-、Zn-、Cd-和Cd-硫蛋白与EDTA和载碳酸酐酶的反应。锌与EDTA的配体取代反应是多相的，在速率表达上既有缔合成分也有解离成分。镉位点的反应性要低2个数量级。相比之下，载碳酸酐酶从Zn-硫蛋白和Zn， cd -硫蛋白中提取锌的二级过程比涉及EDTA的过程快2-3个数量级，接近载碳蛋白对未结合的Zn2+的速度。与其他锌蛋白相比，锌硫蛋白含有异常活性的金属位点，表明该蛋白可能是一种生理锌转运蛋白，能够将锌捐赠给需要锌的载脂蛋白大分子。
The reactions of Zn-, Zn,Cd-, and Cd-thioneins with EDTA and apo-carbonic anhydrase have been studied. The ligand substitution reaction of zinc with EDTA is multiphasic, having both associative and dissociative components in the rate expression. The cadmium sites are about 2 orders of magnitude less reactive. In contrast, apo-carbonic anhydrase abstracts zinc from Zn-thionein and Zn,Cd-thionein in second-order processes that are 2-3 orders of magnitude more rapid than those involving EDTA and approach the rate for unligated Zn2+ with the apo-protein. In comparison with other zinc proteins, Zn-thionein contains unusually reactive metal sites, suggesting that this protein may be a physiological zinc transfer protein, able to donate zinc to zinc-requiring apo macromolecules.