PURIFICATION OF CADMIUM-BINDING PROTEINS FROM RELATED SPECIES OF TERRESTRIAL HELICIDAE (GASTROPODA, MOLLUSCA) - A COMPARATIVE-STUDY
PURIFICATION OF CADMIUM-BINDING PROTEINS FROM RELATED SPECIES OF TERRESTRIAL HELICIDAE (GASTROPODA, MOLLUSCA) - A COMPARATIVE-STUDY
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DOI：
10.1007/bf00577109
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发表时间：
1989-02-21
影响因子：
4.3
通讯作者：
BAUERHILTY, A
中科院分区：
文献类型：
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作者：
DALLINGER, R;BERGER, B;BAUERHILTY, A
对3种陆生螺旋科植物（螺旋果蝇、麻菜蛾和阿利安塔）投喂富镉饲料。蜗牛在它们的肝胰腺中积累了大量的金属。大多数镉和一些锌，在离心后，在可溶性馏分中发现，从镉结合蛋白中分离出每个物种的离子交换和凝胶色谱。这些蛋白质含有不同数量的镉，但很少或没有锌，并且在254 nm处表现出高吸收，表明存在镉-巯基键。凝胶过滤后，发现来自Helix pomatia和Arianta arbustorum的镉结合蛋白分子量为12,000，而来自Cepaea hortensis的镉结合蛋白分子量为10,000。sds -聚丙烯酰胺凝胶电泳结果显示，双螺旋和阿利安塔蛋白各有一条单带，分子量均为11000。氨基酸分析显示，每种蛋白质的半胱氨酸（12-20%）、甘氨酸（15-19%）和丝氨酸（12-14%）含量较高，赖氨酸（9-13%）和丙氨酸（4-8%）含量适度升高，但没有蛋氨酸，只有痕量的芳香氨基酸（如果有的话）。结果表明，双螺旋、麻菜和阿利塔蛋白中镉与半胱氨酸的比例分别为1:5、1:10和1:3。分离蛋白的某些特征与哺乳动物金属硫蛋白相似。然而，大多数特征与真正的金属硫蛋白不同，与某些海洋软体动物中发现的镉结合蛋白相似。
Three species of terrestrial Helicidae (Helix pomatia, Cepaea hortensis and Arianta arbustorum) were fed cadmium-rich diet in the laboratory. The snails accumulated high amounts of the metal in their hepatopancreas. Most cadmium and some zinc were found, after centrifugation, in the soluble fractions from which a cadmium-binding protein was isolated for each species by ion exchange and gel chromatography. The proteins contained different amounts of cadmium, but little or no zinc, and showed high absorption at 254 nm indicating the presence of cadmium-mercaptide bonds. After gel filtration, a molecular weight of 12,000 was found for cadmium-binding proteins from Helix pomatia and Arianta arbustorum, whereas a molecular weight of 10,000 was found for a cadmium-binding protein from Cepaea hortensis. SDS-polyacrylamide gel electrophoresis showed one single band for each protein from Helix pomatia and Arianta arbustorum and suggested a molecular weight of 11,000 for both species. Amino acid analysis revealed, for each protein, high amounts cysteine (12-20%), glycine (15-19%), and serine (12-14%), and moderately elevated contents of lysine (9-13%) and alanine (4-8%), but no methionine and only traces, if any, of aromatic amino acids. The ratios of cadmium to cysteine were 1:5, 1:10, and 1:3 in the proteins from Helix pomatia, Cepaea hortensis and Arianta arbustorum, respectively. Some features of the isolated proteins resembled mammalian metallothioneins. Most characteristics, however, differed from true metallothioneins and were similar to cadmium-binding proteins found in some marine molluscs.