Immunodetection and characterization of allergenic proteins in common buckwheat (Fagopyrum esculentum)

Abstract

Allergenic proteins of molecular mass 22 kDa, 36 kDa, 39-40 kDa and 70-72 kDa were identified from water-soluble fractions of common buckwheat cv. "Miyazaki-zairai". The identification was based on the reactivity of the protein with IgE antibodies from patients' allergic to buckwheat. The allergenic proteins fall within the β and γ subunits of the globulin fraction indicating that the allergenic reactions are contributed by the major storage protein in buckwheat. The 22 kDa protein was the most consistent with IgE activity. N-terminal amino acid sequence of 22 kDa protein showed maximum homology with the seed globulins from both dicot and monocot species. Based on the N-terminal amino acid sequence, two degenerate primers were selected to amplify the cDNA encoding the major allergenic protein. A single PCR product obtained was subsequently sequenced. The deduced amino acid sequence was identical in its N- terminal end. Homology search revealed 94 and 93 % homology to two buckwheat legumin like proteins.