脱金属硫蛋白与镉离子的络合作用及构象研究

用圆二色（ＣＤ）谱地研究兔肝脱金属硫属蛋白的两个亚型与Ｃｄ＾２＋的络合作用及对重组ＭＴ构象的影响。观测了ａｐｏ－ＭＴ垢巯基在空气和室温下的稳定性。在ＰＨ４．７１，镉重组ＭＴ１的ＣＤ谱特征峰在２５７ｎｍ（＋），２３８ｎｍ（－），２２６ｎｍ（＋）与镉诱导的天然ＭＴ１相同。在空气存在和ＰＨ７．９０的ＣＤ谱只有２４３ｎｍ（＋）一个峰。向两亚型分别加入７ｅｑＣｄ＾２＋测定ＣＤ谱随ＰＨ值的变化，发现在ＰＨ２．

The Complexing of apo-metallothionein with Cadmium Ion and Its Conformation Study

The circular dichroism was used to study the complexing of two isoforms of rabbit liver apo-metallothionein(apo-MT)wtih Cd2+ ion and the influence of Cd2+ ion on the conformation of the reconstituted MTs.The stability of the sulfhydryls of apo-MT at room temperature in the presence of air had been followed.It was found that the characteristic CD bands at 257 nm(+),238 um(-), 226 um(+) of the reconstituted MT1 with Cd2+ ion at pH 4.71 was the same as those of the native MT induced by Cadmium. However only one peak at 243mm(+)appeared on the CD spectra pH 7.9.The CD spectra of the two isoforms of apoMTs with added 7eq Cd2+ were measured various pH values.It was found that the peak at 256nm of apo-MT1 with added 7eq Cd2+ ion split into two small peaks between pH 2.42 and pH 3.02,while the shape of the CD band of apo-MT2 with added 7eq Cd2+ion changed from a monopeak to a group of characteristic peaks with increasing pH indicating that the binding sites and pathway of apo-MT1binding to Cd2+ ion were different from those of apo-MT2.