Variability in the fractionation of Cu, Ag, and Zn among cytosolic proteins in the bivalve Macoma balthica

Gel filtration chromatographs of cytosols from the clam Macorna balthica analysed from both field and laboratory treated specimens showed that uptake of Cu, Ag, and Zn in the metallothionein-like protein (MLP) pool follows exposure both in nature and in the laboratory. Specimens collected from San Francisco Bay over 18 mo showed strong temporal variability in the fractionation of the metals among cytosolic proteins. A marked increase in Cu, Ag, and Zn in a very low molecular weight pool occurred when concentrations were highest In the MLP pool. The correlation between total cytosollc metal and MLP-metal also appeared to approach a hyperbolic character at the highest concentrations.