metalothioneins(MTs) fold into two separate domains: β-domain and α -domain which obviously differ in function. Neuronal growth inhibitory factor (GIF), named as Metallothionein -Ⅲ(MT-Ⅲ), is first characterized to be capable of inhibiting the growth of neuronal cell in nervous system, and β-domina is its functional domina. To study deep the the structure and function of MTs, GIF and their domains; we construct the splicing-domains within metallothioneins family, βGIF- αMT-1(βⅢ-αⅠ) and βMT-1-αGIF(βⅠ-αⅢ): cDNAs were amplified by polymerase chain reaction (PCR), inserted into vector pGEX-4T-1, expressed in Esherichia coli as carboxyl teminal extension of glutathione-S-transferase (GST) by ⅠPTG's induction. After the fusion protein had been digested by thrombin on a Glutathione-Sephacryl- S100. Eighty mg of column, recombinat βⅢ－αⅠ and βⅠ－αⅢ were purified by gel fitration on Sephacryl-S100. Eighty mg of the protein can be obtained from evergy liter medium after fermentation. The results of SDS-PAGE, amino acids composition, molecualr mass, the ratio of metal/protein and sulfhydryl group/protein confirm that the purified protein is the desired one. Utraviolet (UV) absorption spectroscopy and circular dichroism (CD) spectroscopy show splicing- domains have the characteristic metal-sulfhydryl group clusters of metallothionein family. βⅢ－αⅠ, similar with GIF, displays the neuronal growth inhibitory activity.

Key words: METALLOTHIONEIN, FERMENTATION, STRUCTURE