Human hepatic metallothioneins: resolution of six isoforms.

Both by analytical and preparative reversed-phase high-performance liquid chromatography (HPLC) human hepatic metallothionein (MT) was resolved into six isoproteins. All six isoforms can be differentiated by amino acid analysis. One of the isoproteins is identical with the previously sequenced charge-separable form MT-2 while the remaining five are subforms of the less negatively charged MT-1 fraction. Comparison of the HPLC profiles obtained from postmortem liver samples of different individuals indicates that invariably all six isoMTs are present in human liver although their relative amounts are varying.