SDS-PAGE analysis of the wild-type ALAD-GST fusion protein.

Expression and purification of GST-ALAD fusion protein and SDS-PAGE were carried out as described in “Materials and methods.” One percent (v/v) of the total volume was loaded to each lane. Proteins were stained with Coomassie brilliant blue. Lane M: molecular weight protein standards; lane 1: transformed E coli PLysS cells without induction; lane 2: transformed E coli PLysS cells after induction with IPTG; lane 3: supernatant from the lysate of induced cells; lane 4: GST-fusion protein purified by glutathione-affinity chromatography.