Zinc-, copper- and cadmium-binding protein in Ehrlich ascites tumour cells.
The properties of Ehrlich ascites tumour cells exposed in vivo to cadmium were investigated as a function of the zinc status of the host animals. Tumour-cell growth was inhibited by cadmium in both zinc-sufficient and zinc-deficient animals. However, cells in zinc-sufficient tumours accumulate much less cadmium than those in deficient tumours. The subcellular distributions of cadmium and zinc do not depend on zinc status. Cadmium and zinc are bound to a low-molecular-weight protein with properties similar to metallothionein. Without exposure to cadmium, a zinc- and copper-binding protein is still present that behaves like a metallothionein. This protein can rapidly bind cadmium added to Ehrlich cells in vitro. It is shown that the zinc- and copper-binding protein contains free thiol groups. Ehrlich cells isolated from cadmium-treated animals are viable and show normal incorporation of uridine into RNA, but the cellular uptake of thymidine and its incorporation into DNA are inhibited.
D000818:Animals; D001202:Ascitic Fluid / Q000378:metabolism; D002104:Cadmium / Q000378:metabolism*; D002286:Carcinoma, Ehrlich Tumor / Q000378:metabolism*; D002352:Carrier Proteins / Q000378:metabolism*; D002852:Chromatography, Ion Exchange; D003300:Copper / Q000378:metabolism*; D005260:Female; D051379:Mice; D013347:Subcellular Fractions / Q000378:metabolism; D013936:Thymidine / Q000378:metabolism; D014529:Uridine / Q000378:metabolism; D015032:Zinc / Q000378:metabolism*
D002352:Carrier Proteins; D002104:Cadmium; D003300:Copper; D015032:Zinc; D013936:Thymidine; D014529:Uridine