Effects of Diethyldithiocarbamate and N-methyl-N-dithiocarboxyglucamine on Murine Hepatic Cadmium-metallothionein in Vitro

A study was made of the effects of diethyldithiocarbamate (DDTC) and N-methyl-N-dithiocarboxyglucamine (MDCG) on partially purified cadmium-metallothionein (Cd-MT) in vitro obtained from livers of mice previously injected with CdCl2 containing 109CdCl2. Analytical Sephadex G-75 gel filtration showed that MDCG effected a time-dependent removal of Cd from MT, and 99% of the Cd was recovered as the soluble Cd(MDCG)2 complex after 24 hr of incubation. Only a portion of Cd of Cd-MT was complexed by DDTC after 24 hr of incubation; 44% remained as Cd-MT, and the net loss following centrifugation prior to application of the samples to the column corresponded to 56% of the Cd originally present. It was proposed that MDCG complexes the 4 g-atoms of Cd in cluster A of MT as well as the 3 g-atoms in cluster B, while DDTC complexes only the 4 g-atoms of Cd in cluster A.