Isolation and Properties of Allergenic Proteins in the Oyster Crassostrea gigas

Two allergens, designated as Crags I and 2, were isolated from the oyster Crassostrea gigas by gel permeation chromatography on a Sephacryl 5-300, ion-exchange FPLC on a Mono Q HR 5/5, and reverse-phase HPLC on a TSKgeI Phenyl 5PW-RP.Although both allergens were separated from each other by ion-exchange FPLC, they showed the same behaviors in gel permeation chromatography and reverse-phase HPLC.In addition, Crags were quite similar to each other as follows: they were 86 kDa glycoproteins with a carbohydrate content of about 5%; they were composed of 35 kDa subunits; they were remarkably abundant in Gix, followed by Asx, Ala, and Leu, and were devoid of Pro and Trp; their reactivities against the sera from seafood allergy patients were equivalent.The molecular masses and characteristics of amino acid composition strongly suggested that Cra gs are tropomyosin of C. gigas.