HIGH-PERFORMANCE LIQUID-C CHROMATOGRAPHY FOR STUDYING METALLOTHIONEIN POLYMORPHISM

Four commercially available metallothioneins from rabbit liver (RL, RL I, RL II) and from horse kidney (HK) have been studied by size exclusion chromatography and by reverse phase chromatography, to characterize their polymorphism. The isoforms are detected by UV at 250 nm. Separations by size exclusion show that the metallothioneins are partially dimerized, with molar rates of dimer ranging from 5% for HK to 15% for RL II. The four chromatograms obtained by reverse phase exhibit a different morphology: RL separates in four main isoforms, RL I into two, RL II into three, and HK into two. An attribution of the various peaks for the RL, RL I, and RL II series is proposed. The comparable results obtained by the two methods allow us to estimate that RL is composed of 20-30% RL I and 70-80% of RL II.