Chromatographic analysis of low-molecular-mass copper-binding ligands from the crab species Scylla serrata and Portunus pelagicus.

Two copper-binding proteins and a zinc-binding ligand were isolated from the hepatopancreas of the crab Portunus pelagicus. The copper-binding proteins behave similarly to those from the crabs Carcinus maenas and Scylla serrata, and were shown to be metallothioneins. Reversed-phase high-performance liquid chromatographic (HPLC) analysis confirmed the relative purity of both proteins with only cross-contamination between the two different forms of metallothioneins, and offers a good method to separate the two forms of metallothioneins. The vast difference in the retention times (and hence the hydrophobicity) in reversed-phase HPLC indicates that the two proteins could be conformationally very different.