Discovery of HB-EGF binding peptides and their functional characterization in ovarian cancer cell lines

a Amino acid sequence of recombinant protein (His)6-sHB-EGF. The shadow area remarks His-tag (6？×？His). The bold italic part indicates enterokinase cutting site. The underlined part represents human sHB-EGF (63–149 AA). b Verification of the expression of recombinant protein through 15% SDS-PAGE. M: protein marker, Lane 1: the lysate of BL21; Lane 2: BL21 containing pET-30a; Lane 3: BL21 containing pET-30a-His-HB-EGF without IPTG induction; Lane 4: BL21 containing pET-30a-His-HB-EGF with IPTG induction. c Verification of the expression of recombinant protein by western blot. Lanes 1–4 are identical to those in b. The antibody used here is anti-His antibody. d Verification of the expression of recombinant protein by western blot. Lane 1: the lysate of BL21 containing pET-30a-His-HB-EGF without IPTG induction; Lane 2: above BL21 with IPTG induction. The antibody used was anti-HB-EGF antibody. e SDS-PAGE after Ni-NTA and heparin affinity chromatography. Lanes 1 and 2: two most concentrated elution fractions from each affinity chromatography. f Detection of protein before and after enterokinase digestion by western blot. Lane 1: before enterokinase digestion. Lane 2: after enterokinase digestion. The antibody used was anti-HB-EGF antibod