Cadmium-binding proteins of three marine molluscs and characterization of two cadmium-binding glycoproteins from the hepatopancreas of a whelk, Buccinum tenuissimum.

The cadmium-binding proteins were shown to exist in the hepatopancreas of three molluscs, a whelk, Buccinum tenuissimum, a turbo, Batillus cornutus, and a squid, Todarodes pacificus. Cadmium was efficiently accumulated in nature to a mean concentration of 119, 33, and 50 micrograms/g wet tissue in the hepatopancreas of three species of molluscs, and 30%, 11%, and 43% of the element in each tissue of whelk, turbo, and squid was extracted to the soluble fraction, respectively. Separation of the soluble fraction by Sephadex G-75 in the presence of 2-mercaptoethanol revealed that cadmium was mainly bound to the protein fraction FII of molecular weight 10,000. Two cytoplasmic cadmium-binding glycoproteins from the hepatopancreas of Buccinum tenuissimum were purified to homogeneity by Sephadex G-75 gel filtration and double DEAE-Sephadex A-25 chromatographies in the presence of 2-mercaptoethanol. These two cadmium-binding glycoproteins, termed FIIA and FIIB, had molecular weights of 8000 and 13,000 and consiste...