Xie Lingtian, Klerks Paul L
Department of Biology, University of Louisiana at Lafayette, P. O. Box 42451, Lafayette, Louisiana 70504, USA.
Environ Toxicol Chem. 2004 Jan;23(1):173-7. doi: 10.1897/02-652.
Metallothioneins (MTs) are a class of low molecular weight, cysteine-rich, metal-binding proteins ubiquitous in animals. They function in metal regulation and detoxification. An MT-like protein was separated by gel-permeation high-performance liquid chromatography (HPLC) in the least killifish Heterandria formosa exposed to 6 mg/L of Cd for 26 h. Western blot analysis showed that this protein cross-reacted with a cod-MT antibody. We quantified MT-like protein levels by the Cd-hemoglobin saturation assay in fish from two Cd-resistant and two control laboratory populations. Fish from the resistant populations had higher MT-like protein levels than those from the control populations; this difference was found for basal levels and for levels after 26 h of exposure to Cd. Our results suggest that the MT-like protein detoxified Cd in the least killifish and accounted for at least part of the increased resistance in the Cd-resistant laboratory populations.
金属硫蛋白（MTs）是一类低分子量、富含半胱氨酸、在动物体内普遍存在的金属结合蛋白。它们在金属调节和解毒过程中发挥作用。通过凝胶渗透高效液相色谱（HPLC）从暴露于6 mg/L镉26小时的美鳉（Heterandria formosa）中分离出一种类MT蛋白。蛋白质印迹分析表明，该蛋白与鳕鱼MT抗体发生交叉反应。我们通过镉-血红蛋白饱和试验对来自两个耐镉和两个对照实验室群体的鱼类中的类MT蛋白水平进行了定量。来自耐镉群体的鱼类的类MT蛋白水平高于对照群体的鱼类；在基础水平和暴露于镉26小时后的水平上均发现了这种差异。我们的结果表明，类MT蛋白使美鳉体内的镉解毒，并至少部分解释了耐镉实验室群体中抗性增加的原因。
