ISOLATION OF CD-BINDING PROTEIN OF WATER HYACINTH (EICHHORNIA-CRASSIPES) GROWN IN NILE-RIVER WATER

Many investigators have reported that water hyacinth plants can accumu late toxic heavy metal ions and may be useful for elutriation of pollu ted water. The purpose of our study was to search for the mechanism by which these plants tolerate and accumulate toxic metal ions. Cadmium was accumulated in the plants against the concentration gradient, most ly as a soluble form in the cytoplasm. Isolation and Purification of C d-binding protein with sephadex A-25 and fractionation on sephadex G-1 00 showed that the accumulated Cd was associated with two major protei n fractions. The first with molecular weight 25 - 20 kD contained abou t 35% of bound Cd. The second fraction with molecular weight 12 - 8 kD contained about 40% of bound Cd. The two forms were found also in wat er hyacinth cultivated in Nile water as a control, although the amount of Cd accumulated was less than those exposed to excess Cd.