镉和铅对鹌鹑肝脏金属硫蛋白的诱导

鹌鹑（Coturnix cotumix japonica）经口染毒CdCl₂溶液或CdCl₂和PbCl₂混合溶液，16 d后剖杀，取肝脏，Sephadex G-75柱层析得到肝脏金属硫蛋白(metallothionein，MT).经氨基酸组分检测分析其生化特性，结果表明纯化所得蛋白具有63个氨基酸残基，半胱氨酸含量为31.83%，分子量为6 614 Da，与哺乳动物金属硫蛋白的生化性质相类似.运用镉-血红蛋白饱和法对鹌鹑肝脏中MT进行定量测定，结果显示镉和铅可诱导鹌鹑肝脏内MT合成的增加，且肝脏中MT的含量随着金属暴露浓度的增加显著提高.这表明鹌鹑体内MT维持重金属内稳态的机制可能和哺乳动物体内的极为相似.

Influence of Cadmium and Lead to the Metallothionein in the Liver of the Quails (Coturnix coturnix japonica)(Chinese)

The quails,Coturnix coturnix japonica, were fed with saline of CdCl_2 or mixture of CdCl_2 and PbCl_2 orally,and were sacrificed after 16 days.The cadmium binding metallothionein was purified from the quail liver by the Sephedax G-75 permeation chromatography and centrifugal devices for concentration.After that the protein was tested by UV spectrophotometer and analysis of amino acid composition.The results demonstrate that the quail metallothionein contains 63 amino acid residuals,which has the general biochemical properties of mammal metallothionein: spectroscopic feathers typical of cadmium thiolate clusters,low molecular weight(6 614 Da),high metal(cadmium) content and the high level of cysteine content(about 31.82%).The cadmium-hemoglobin saturation assay was applied for quantification of metallothionein in the quail liver,the results showed that the synthesis of metallothionein in the quail liver can be induced by heavy metal cadmium and lead,and the amount of the liver metallothionein was increased with the heavy metal concentration exposed.The induction of metallothionein in the quail liver suggests that the heavy metal homeostasis mechanism in quails may have evolved similarly to mammals.