Isolation and characterisation of metallothionein from Antarctic clam Laternula elliptica

Abstract

Antarctic clam, Laternula elliptica, adapted for survival in high concentrations of heavy metal induce metallothionein in the presence of Cadmium. In this study, we isolated and characterized a cadmium-binding protein, metallothionein, from metal-exposed clams, L. elliptica. Purification by gel-permeation and ion-exchange chromatography showed that the metal is bound principally to newly formed proteins. The molecular weight of the purified metallothionein was determined as 7.27 kDa by MALDI-TOF MS analyses. The absorption spectra profiles indicate Cd-metallothioneins complexes, and there is a 4 nm red shift of the unresolved lowest energy absorption band when 5 equiv of Cd(II) is incorporated.