Identification of metallothionein isoforms with capillary zone electrophoresis using a polyacrylamide-coated tube

Metallothionein (MT) isoforms from various liver tissues were separated with capillary zone electrophoresis (CZE) using a polyacrylamide-coated tube at neutral pH. The electrophoresis was performed on MT-1 and MT-2 purified from mouse, rat, rabbit and human livers. The retention times of mouse and rat MT-1 coincided, while the retention times of rabbit and human MT-1 were longer. The retention times of MT-2 purified from the four sources were the same. MT-1 and MT-2 separated more definitely with N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid (HEPES)-Tris buffer (25 mM, pH 7.4) than with N-tris(hydroxymethyl)methyl-3-aminopropane sulfonic acid (TAPS)-Tris buffer (25 mM, pH 7.7) or with N-(2-acetamido)iminodiacetic acid (ADA)-Tris buffer (25 mM, pH 7.4). In addition, liver MT isoforms prepared from Zn- or Cd-administered mice could be separated.