Transition series metals and sulfhydryl reagents induce the synthesis of four proteins in eukaryotic cells

Abstract

Several transition series metals (copper, cadmium, zinc and mercury) and the sulfhydryl reagent, sodium arsenite, enhance the synthesis of specific proteins in chick embryo cells and in human foreskin cells in culture. The proteins are visible 1--3 h after exposure to concentrations ranging from 10 microM to 100 microM depending upon which reagent is used. These proteins comigrate on acrylamide gel electropherograms with the proteins induced by two copper-chelating drugs, kethoxal bis(thiosemicarbazone) and disulfiram, and by heat shock. However, these proteins migrate in a significantly different manner than do the canavanine-enhanced proteins. The four proteins induced in chick embryo cells are distinct from one another as determined by partial proteolytic mapping. Simlarly, the three proteins induced in human cells are distinct. However, the 100-kilodalton and the 70-kilodalton proteins from chick and from human cells appear to be related as judged by this mapping procedure. The 70 kilodalton protein enhanced by kethoxal bis(thiosemicarbazone), disulfiram, arsenite and heat shock have a high degree of similarity according to this technique. The arsenite and canavanine-enhanced 100-kilodalton proteins are related as are the arsenite-enhanced 70-kilodalton and the canavanine-enhanced 75-kilodalton proteins. The canavanine-enhanced 30 kilodalton protein resembles the arsenite-enhanced 25-kilodalton protein rather than the 35-kilodalton species. In view of these findings, it appears that a variety of treatments, namely, chelating drugs, transition series metals, sulfhydryl reagents, heat shock, and amino acid analogous can induced similar, if not identical, proteins in eukaryotic cells.