ABSTRACT
<p><b>OBJECTIVE</b>To establish a method for the expression of glycogen synthase kinase 3β with high purity and biological activity.</p><p><b>METHODS</b>E.coli expression system and baculovirus-insect cell expression system were used to produce the kinase, followed by purification using His-tag and GST-tag and determination of its purity and activity by SDS-PAGE and kinase reaction, respectively.</p><p><b>RESULTS</b>Glycogen synthase kinase 3β produced from E.coli represented 54% of the total bacterial protein, as compared with 96% of the total protein from the insect cell system .Glycogen synthase kinase 3β produced from insect cell exhibited an one-fold higher biological activity than the protein obtained from E.coli.</p><p><b>CONCLUSIONS</b>Compared with the protein from E.coli system, glycogen synthase kinase 3β from the insect cell expression system is endowed with a higher purity and bioactivity.</p>