Separation of metallothionein isoforms by micellar electrokinetic capillary chromatography

Current techniques for the separation and quantification of metallothionein isoforms have limited value for routine analysis. Isoforms having a similar charge have been separated successfully using reversed-phase HPLC but this technique suffers from a slow sample turnover time. The use of the surfactant sodium dodecyl sulphate for the separation of metallothionein isoforms by micellar electrokinetic capillary chromatography (MECC) is described. The charge-different isoforms MT-1 and MT-2 from rats, rabbits and sheep were separated within 9-12 min. In addition, a varying degree of heterogeneity was observed in purified samples of human MT-1, rat MT-2, rabbit MT-1, rabbit MT-2 and sheep MT-1. The behaviour of chicken MT was different from that of any other species. The separation of sheep liver extracts indicated the potential of MECC as the basis for a quantitative assay for both charge-different and charge-similar metallothionein isoforms.