Enhanced Approaches for Identifying Amadori Products: Application to Peanut Allergens

Authors

Katina L. Johnson, National Institute of Environmental Health Sciences (NIEHS)
Jason G. Williams, National Institute of Environmental Health Sciences (NIEHS)
Soheila J. Maleki, USDA-ARSFollow
Barry K. Hurlburt, USDA-ARSFollow
Robert E. London, National Institute of Environmental Health Sciences (NIEHS)Follow
Geoffrey A. Mueller, National Institute of Environmental Health Sciences (NIEHS)Follow

Date of this Version

2016

Citation

J. Agric. Food Chem. 2016, 64, 1406−1413

Comments

This article not subject to U.S. Copyright. Published 2016 by the American Chemical Society

Abstract

The dry roasting of peanuts is suggested to influence allergic sensitization as a result of the formation of advanced glycation end products (AGEs) on peanut proteins. Identifying AGEs is technically challenging. The AGEs of a peanut allergen were probed with nano-scale liquid chromatography−electrospray ionization−mass spectrometry (nanoLC−ESI−MS) and tandem mass spectrometry (MS/MS) analyses. Amadori product ions matched to expected peptides and yielded fragments that included a loss of three waters and HCHO. As a result of the paucity of b and y ions in the MS/MS spectrum, standard search algorithms do not perform well. Reactions with isotopically labeled sugars confirmed that the peptides contained Amadori products. An algorithm was developed on the basis of information content (Shannon entropy) and the loss of water and HCHO. Results with test data show that the algorithm finds the correct spectra with high precision, reducing the time needed to manually inspect data. Computational and technical improvements allowed for better identification of the chemical differences between modified and unmodified proteins.