Isolation and Partial Characterization of a Cadmium-binding Protein in Soybeans from a Cadmium-polluted Field

抄録

The isolation and partial characterization of a cadmium-binding protein from soybeans harvested in a cadmium-polluted field were performed. Sephadex G-75 chromatography of the cadmium fraction with an apparent molecular weight of 10, 000, which was released from the macromolecules in the presence of 2-mercaptoethanol, showed two components with apparent molecular weights of 22, 000 and 9200. The cadmium fraction gave a Coomassie-blue staining band at Rf 0.92 and a weakly stained zone at about Rf 0.6 on polyacrylamide gel electrophoresis. Amino acid composition analysis of the cadmium fraction revealed a low half-cystine content and high acidic amino acids contents. SDS-Polyacrylamide gel electrophoresis of the cadmium fraction gave a single band at a position corresponding to a molecular weight of 21, 000 and a broad band at one corresponding to about 9000. The cadmium component of a molecular weight of 21, 000 bound tightly to DEAE-Sephadex A-25 resin.