Meisch H U, Schmitt J A
Environ Health Perspect. 1986 Mar;65:29-32. doi: 10.1289/ehp.866529.
A low molecular weight Cd-binding phosphoglycoprotein, cadmium-mycophosphatin, has been isolated from the mushroom Agaricus macrosporus. This protein has a molecular weight of 12,000 dalton and contains no sulfur but a high amount of acid amino acids (Glu, Asp), and carbohydrates (glucose, galactose). Cadmium-mycophosphatin has an isoelectric point less than pH 2, binds cadmium with a dissociation constant of KD = 1.59 X 10 M (pKD = 6.8) and is saturated with 13.5 mole Cd/mole, all Cd-binding sites being equivalent. It is suggested that Cd is bound by phosphoserine groups, similar relations being known from calcium-binding proteins in animals. From A. macrosporus four other low-molecular weight glycoproteins have been isolated which contain sulfur and bind cadmium and copper. The biological significance of these Cd-binding proteins is discussed.
一种低分子量的镉结合磷酸糖蛋白——镉-真菌磷酸蛋白，已从大孢蘑菇中分离出来。这种蛋白质分子量为12,000道尔顿，不含硫，但含有大量酸性氨基酸（谷氨酸、天冬氨酸）和碳水化合物（葡萄糖、半乳糖）。镉-真菌磷酸蛋白的等电点小于pH 2，以KD = 1.59×10 M（pKD = 6.8）的解离常数结合镉，并且每摩尔可饱和结合13.5摩尔镉，所有镉结合位点都是等效的。有人认为镉是通过磷酸丝氨酸基团结合的，动物中的钙结合蛋白也存在类似关系。从大孢蘑菇中还分离出了其他四种低分子量糖蛋白，它们含有硫并能结合镉和铜。文中讨论了这些镉结合蛋白的生物学意义。
