Western blotting for confirmation of expression of human epidermal growth factor in clones having expression cassettes. Lanes 1-3, Bands appeared on nitrocellulose membrane after NBT/BCIP treatment showing successful expression of hEFG in clones containing pET-EGF-C1, pET-EGF-C2 and pET-EGF-C3 respectively. Lane 4, Un-induced sample used as negative control. No band appeared for negative control.