Structural studies on allergen RC-13 from Ricinus communis L.: isolation and characterization of a major glycopeptide

RESUMO

A glycoprotein, RC-13, isolated from Ricinus communis seeds was reduced, S-alkylated and cleaved by trypsin. The tryptic digest was fractionated by ion-exchange chromatography and a glycopeptide was isolated and purified by high-voltage paper electrophoresis. When submitted to amino acid and carbohydrate analyses this major glycopeptide showed the following chemical composition Lys1, Asp1, Thr2, Ser4, Glu1, Pro2, Gly2, Ala2, Val2, GlcN6, Man6 and Gal8. Hydrazynolysis positioned Ser as the C-terminal residue. It is postulated that this glycopeptide belongs to the C-terminal region of the allergen