RAPID INDUCTION OF COPPER-BINDING PROTEINS IN THE GILLS OF METAL EXPOSED MUSSELS

Abstract

This chapter discuses the rapid induction of copper-binding proteins in the gills of metal exposed mussels. The sublethal concentrations of Cu 2+ (0.08 ppm) rapidly induce the synthesis of thionein-like copper-binding proteins in the gills of the mussel, Mytilus qalloprovincialis Lam. When soluble fractions from the gills of mussels have been exposed for 24–48 h to Cu 2+ are eluted through gel filtration columns (Sephadex G-75), essentially 3 copper containing peaks are obtained; they demonstrate that copper is associated (1) with high molecular weight proteins, (2) with proteins of approximately 12.000 molecular weight, and (3) with a fraction having the same elution volume as free copper. On the other hand, in the gills from controls as well as from mussels exposed for 4 h to copper ions, the metal is not significantly associated with soluble proteins having a molecular weight of about 12.000. These results could indicate that copper stimulates the synthesis of low molecular weight copper-binding proteins in the gills of mussels. Studies with 35 S labeled cysteine as a precursor amino acid strongly support this assumption.