Characterization of the Metallothioneins Induced in HeLa Cells by Dexamethasone and Zinc

The metallothioneins induced in HeLa cells by dexamethasone and Zn2+ were labeled with [3H]cysteine and [35S]cysteine respectively. These labeled metallothioneins were compared to one another and to metallothioneins from human liver by (a) gel permeation chromatography on Sephadex G-75 columsn, (b) ion-exchange chromatograhy on DEAE-Sephadex A-25 columns, (c) electrophoresis on non-denaturing polyacrylamide gels, and (d) electrophoresis of reduced and alkylated proteins on dodecylsulfate/polyacrylamide gels. The dexamethasone-induced metallothioneins of HeLa cells, the Zn2+-induced metallothioneins of HeLa cells, and the metallothioneins of human liver were indistinguishable by these four criteria.