A low-molecular-weight cadmium-binding substance in human and rat livers and human blood.

A cadmium-binding substance with a molecular weight even lower than that of metallothionein was demonstrated on Sephadex G-75 gel filtration chromatography of the soluble fractions from newborn human and adult rat liver homogenates and adult human hemolysate which were mixed with CdCl2 in vitro. This substance was purified from rat liver extracts by gel filtration and ion-exchange column chromatography and characterized by 6 M guanidine X HCl thin-layer gel filtration chromatography and N-terminal and total amino acid analyses. The results showed that the isolated low-molecular-weight cadmium-binding substance was a cadmium-reduced glutathione complex, whose molecular weight was found to be approximately 1400 by Sephadex G-15 gel filtration.