The orally bioavailable copper salt of D-gluconic acid. In addition to its roles as an enzyme cofactor for cytochrome C oxidase and superoxide dismutase, copper forms complexes with the thiocarbamate disulfiram (DSF) forming DSF-copper complexes, which enhances the DSF-mediated inhibition of the 26S proteasome; proteasome inhibition may result in inhibition of cellular protein degradation, cessation of cell cycle progression, inhibition of cellular proliferation, and the induction of apoptosis in susceptible tumor cell populations. Check for active clinical trials using this agent. (NCI Thesaurus)