Peanut allergens attached with p-aminobenzamidine are more resistant to digestion than native allergens

Authors: Chung, Si Yin; Reed, Shawndrika; Zhang, Dunhua

Submitted to: Polish Journal of Food and Nutrition Sciences
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/2/2016
Publication Date: 12/5/2016
Citation: Chung, S., Reed, S.S., Zhang, D. 2016. Peanut allergens attached with p-aminobenzamidine are more resistant to digestion than native allergens. Polish Journal of Food and Nutrition Sciences. 7:1352-1363.

Interpretive Summary: Peanut allergen is a protein that can cause an allergic reaction in peanut-allergic individuals, following ingestion of peanuts. During ingestion, the allergens are digested into small peptide fragments which ultimately are absorbed into the bloodstream and elicit an allergic reaction. We speculated that making peanut allergens resistant to digestion may prevent digestion of the allergens, and, thereby, an allergic reaction. The objective of this study was to make peanut allergens resistant to digestion by covalently attaching p-aminobenzamidine (pABA), a trypsin inhibitor, to the allergens in a peanut extract, and demonstrating that the resulting pABA- allergen conjugates would be resistant to digestion by trypsin. In the experiments, the allergen conjugate was either treated with trypsin or added to a peanut extract containing original peanut allergens in the presence of trypsin. Results showed that the pABA-allergen conjugate was not digested by trypsin, and that it prevented the digestion of original peanut allergens by trypsin. We concluded that pABA, when attached to peanut allergens, could prevent digestion of the allergens by trypsin. The pABA-allergen conjugate may thus serve as a model for making peanut allergens indigestible.

Technical Abstract: Undigested foods are excreted rather than absorbed and therefore, peanut allergens, if undigested, may not cause an allergic reaction in peanut-allergic individuals. Our objective was to make peanut allergens more resistant to digestion by preparing allergen conjugates and demonstrating that the conjugates would be resistant to trypsin digestion. We prepared allergen conjugates in a solution or on a PVDF membrane by covalently attaching p-aminobenzamidine (pABA), a protease inhibitor, to peanut allergens using glutaraldehyde. A control conjugate was also prepared using glycine instead of pABA. Results (SDS-PAGE) showed that the pABA-allergen conjugate was not digested by trypsin, and the profile varied depending on the trypsin concentration. When added to a peanut extract, the conjugate inhibited digestion of native allergens from a peanut extract. By contrast, the glycine conjugate did not inhibit trypsin digestion. The results suggest that pABA, when attached to peanut allergens, could prevent digestion of the allergens by trypsin, and the potential to inhibit digestion may vary depending on the trypsin concentration.