Intracellular copper transport in cultured hepatoma cells.
The distribution of copper in lysates prepared anaerobically from copper-resistant hepatoma cells radiolabeled with 67Cu was examined in pulse-chase experiments. Initially, the majority of the radioactivity (greater than 85%) coeluted with copper-metallothionein. As the chase time increased there was a gradual loss of 67Cu from metallothionein, with a concomitant increase in the level of 67Cu-labeled glutathione. There was also an increase in 67Cu incorporation into superoxide dismutase. These results suggest that the chelation of copper by metallothionein from a copper-glutathione complex (Freedman, J. H., Ciriolo, M. R., and Peisach, J. (1989) J. Biol. Chem. 264, 5598-5605) is a reversible process. Further, they demonstrate that the copper bound to metallothionein is not permanently sequestered, but can be incorporated into other copper proteins.
Freedman
J H
JH
Institute for Structural and Functional Studies, University City Science Center, Philadelphia, Pennsylvania 19140.
Peisach
J
J
D001692:Biological Transport; D006528:Carcinoma, Hepatocellular / Q000201:enzymology / Q000378:metabolism*; D003300:Copper / Q000493:pharmacokinetics*; D005980:Glutathione Reductase / Q000378:metabolism; D006801:Humans; D008113:Liver Neoplasms; D008668:Metallothionein / Q000378:metabolism*; D013482:Superoxide Dismutase / Q000378:metabolism; D014407:Tumor Cells, Cultured / Q000201:enzymology / Q000378:metabolism
D003300:Copper; D008668:Metallothionein; D013482:Superoxide Dismutase; D005980:Glutathione Reductase