The immunoreactivity of Cra a 4 decreased after Maillard reaction with xylose and glucose

Abstract

Cra a 4 is a heat stable allergen in oyster, the effect of Maillard reaction on the immunoreactivity and structure of Cra a 4 was investigated. Firstly, Cra a 4 was cloned, expressed and identified. The purified Cra a 4 was incubated with xylose at 100 °C, pH 8.5 for 30 min or with glucose for 60 min. After Maillard reaction, the IgE-binding activity of Cra a 4 and in vitro digested samples was reduced by about 50%. The unfold α-helix and higher surface hydrophobicity of glycated Cra a 4 were identified as the reason for hypo-immunoreactivity. The higher frequency of lysine (13%) in the primary structure and exposure on the surface of the spatial structure was attributed to the hypo-immunoreactivity of Cra a 4 after Maillard reaction. It comprehensively evaluated the effects of Maillard reaction on Cra a 4 and provids new methods for the industrial production of hypoallergenic oyster. The modified Cra a 4 by Maillard reaction could be a hypoallergenic therapeutic agent for allergy to oyster.

Keywords

• immunoreactivity
• maillard reaction
• oyster
• sarcoplasmic-calcium-binding protein
• structure