Isolation and Quantification of Cadmium and Copper-Species in Lettuce Plants

Abstract

Cadmium and copper-species from native lettuce plants were isolated and quantified after Ultra Turrax homo-genization in buffer and subsequent ultracentrifugation and gel filtration of the cytosol. From the cytoplasma, a high molecular weight metal binding-protein (>75000 g/mol) containing 55% of the cytoplasmic cadmium and 20% of the cytoplasmic copper and a low molecular weight metal binding-protein (3200 g/mol) containing 45% of the cytoplasmic cadmium and 70% of the cytoplasmic copper were isolated. Beside these there were two more copper binding-proteins of about 57000 and 25000 g/mol, containing only small percentage of copper. The solid fragments of the cell, containing 50% of the total cadmium and 20% of the total copper respectively were not further examined. A broad variation in the metal balance from plant to plant was observed.