Sequencing of soy oil and soy lecithin allergens

Abstract Rationale It has been shown that soy oil and soy lecithin may contain allergens. The aim of the present study is to characterize, by means of the physico-chemical and immunological methods, the allergenic proteins of soybean seed transferred to soy oil and soy lecithin during industrial refining. Methods Extraction of proteins was conducted using a buffer solution. The identification of allergens used specific IgE from a soybean allergic patient. Bi-dimensional electrophoresis and sequencing from N and C terminals were used to characterize the allergenic proteins. Results Two allergenic proteins present in soybean seed, soy oil and soy lecithin have been isolated and identified: one 56 kDa non glycosylated allergen, whose isoelectric point of 5.4 has been identified as soybean β-Amylase (7S). One 20 kDa non glycosylated allergen, whose isoelectric point of 4.6 has been identified as Kunitz Trypsin inhibitor [Glycine max] (2S). Conclusions We have sequenced two allergenic proteins present as hidden allergens in soy oil and soy lecithin. It is to note that these highly refining-resistant proteins are not the main proteins of soybean seed.