Molecular weight determination of toxin protein from E. coli isolate pe16

E. coli isolate pe16, when subjected to PCR analysis showed positive forStx2f. Protein from this isolate was subjected to purification. The purification scheme involved ammonium sulphate precipitation at 40% saturation and then at 60% saturation, dialysis using 1% sucrose solution followed by Ion exchange chromatography. DEAE Cellulose for anion and CMC for cation were used as packing materials. Elutions obtained from above purification steps were subjected to protein estimation by Lowry’s method. Crude and purified samples were analyzed by SDS-PAGE using molecular weight markers, to determine molecular weight and purity of the samples. It was observed that crude sample showed more of bands compared to ammonium sulphate precipitation and dialysis. From SDS-PAGE the purity of isolate confirmed a band with 7 kDa protein.