SDS-PAGE and immunoreactivity of recombinant Ama r 1 (rAma r 1). (a) Lane MW: molecular weight marker (GE Healthcare, Little Chalfont, UK); lane 1: Coomassie Brilliant Blue-stained SDS-PAGE of soluble fraction of cell culture (IPTG-induced pET-21b(+) without insert); lane 2: rAma r 1 (IPTG-induced pET-21b(+)/Aca f 1) in soluble fraction; and lane 3: purified rAma r 1 (as an approximately 19 kDa recombinant protein) with Ni-NTA affinity chromatography on 12.5% acrylamide gel. (b) IgE immunoblot of purified rAma r 1 using sera of patients with respiratory allergies. Lanes 1–10: probed with sera from patients with positive for rAma r 1; lane NTC: negative control.