Cadmium-Binding in Human Liver and Kidney

Abstract

Autopsy specimens of liver and kidneys from 40 patients have been analyzed for cadmium and zinc. Sephadex chromatography was performed on soluble extracts from these tissues. In samples from 19 patients a cadmium-binding protein was found. The mean cadmium content of kidney in this group was higher than the corresponding value for all 40 patients. A molecular weight of 10 to 12,000 was estimated for the cadmium-binding protein by Sephadex chromatography. Isoelectric focusing resolved two peaks with pl 4.8 and pl 6.0, the OD₂₅₄/OD₂₈₀ ratio for both peaks being about 5. These data indicate that humans without known occupational exposure to cadmium do have a cadmium-binding protein similar to metallothionein in their liver and kidney.