ABSTRACT
Mammal metallothionein(MT) folds into two separate domains that exhibit different structure and metal binding propertity independently, the study of the strategy of metal ions binding with MT would give better understanding of their exact biological functional mechanisms. In this study, a method using eletrospray ionization mass spectrometry (ESI-MS) phase liquid chromatography and identified by ESI-MS. Different amounts of Cd or Cu were then added in MT-2a samples and ESI-MS was employed to determine the mass difference of MT in different samples. The results Cd2+4S11; while Cd is attached in separate binding sites for the formation of Cd2+3S9 cluster, which intermediately formed with five and six Cd ions were detected. For the Cuprous ions, it prefers to cooperatively bind in β-domain with the form of Cu4-MTβ. The binding form in β-domain would convert from Cu4 into more Cu binding form with the addition of Cu. When high concentration of Cu was added in samples, the result suggested that