摘要
金属硫蛋白是生物体中可由重金属诱导而产生的一种小分子蛋白质，与生物的重金属中毒现象密切相关，并可能参与锌和铜在生物体中的正常代谢过程。以往在海生哺乳类、鱼类、甲壳类和贝类等动物中曾发现此种蛋白质，其主要特征均与Margashe and Vallee首次在马肾皮质部发现的金属硫蛋白(metallo thionein。以后简称MT．)相似。但在海洋以及淡水藻类中的情形如何，迄今仍无报道。
Metallothioneins have been extensively studied in mammals.The Pro sence of these Proteins is also established in marine animals,including vertebrate and invertebrate. But there is no report concerned with eu-caryotic algae.In our laboratory metallothionein was isolated and characterized from the Cd-exposed Ulva pertusa. The algae were kept for four days in artificial seawater containing 0.5 ppm of Cd2+. The samples were homogenized and isolated. The final soluble fraction was applied to Sepha dex G-75 column. Those eluted fractions containing Cd were Pooled and applied to DEAE cellulose column. The eluted fractions were analysed for absorbance at 280 nm and 250 nm,as well as for the content of cadmium, SH and proteins.The low molecular weight Proteins induced by Cd2+ showed a lot of characteristics of metallothionein,such as the high content of SH, low molecular weight (approximately 10,000 as measured by gel filtration), little absorbance at 280 nm, stability of heat and a high metal binding capacity.Metallothioneins were absent in the non-Cd-exposed algae.
