Purification and Characterization of a Cd-Binding Complex from the Root Tissue of Water Hyacinth Cultivated in a Cd2+-Containing Medium

A Cd-binding complex was isolated from water hyacinth root tissueby chromatography with DEAE-cellulose and Sephadex G-50 columnsfollowed by rechromatography on another DEAE-cellulose column.The Cd-binding complex showed a shoulder at 265 nm in the UVabsorption spectrum and three bands at 234 (negative), 256 nm(negative), and 277 nm (positive) in the CD spectrum. The peptideportion of the complex was composed of only glutamic acid and/orglutamine, cysteine, and glycine in a molar ratio of 10 : 10: 4. The molecular weight of the complex was 4,000 at neutralpHs but became lower when the complex was treated with mercaptoethanolor acid, suggesting that the complex consists of multiple oligopeptides. These results indicate that water hyacinth root Cd-bindingcomplex is identical to fission yeast Cd- BP1, composed of twoeach of cadystins A and B. (Received May 16, 1986; Accepted July 14, 1986)