Characterization of low molecular weight allergens from English walnut (Juglans regia)

Melanie L. Downs, Aida Semic-Jusufagic, Angela Simpson, Joan Bartra, Montserrat Fernandez-Rivas, Neil M. Rigby, Steve L. Taylor, Joseph L. Baumert, E. N.Clare Mills

Research output: Contribution to journalArticle

14 Scopus citations

Abstract

Although English walnut is a commonly allergenic tree nut, walnut allergens have been poorly characterized to date. The objective of this work was to characterize the natural, low molecular weight (LMW) allergens from walnut. A protocol was developed to purify LMW allergens (specifically 2S albumins) from English walnuts. In addition to 2S albumins, a series of peptides from the N-terminal region of the 7S seed storage globulin proprotein were also identified and characterized. These peptides comprised a four-cysteine motif (C-X-X-X-C-X10-12-C-X-X-X-C) repeated throughout the 7S N-terminal region. Upon IgE immunoblotting, 3/11 and 5/11 sera from walnut-allergic subjects showed IgE reactivity to the 7S N-terminal fragments and 2S albumin, respectively. The mature 7S protein and the newly described 7S N-terminal peptides represent two distinct types of allergens. Because the proteolytic processing of 7S globulins has not been elucidated in many edible plant species, similar protein fragments may be present in other nuts and seeds.

Original languageEnglish (US)
Pages (from-to)11767-11775
Number of pages9
JournalJournal of Agricultural and Food Chemistry
Volume62
Issue number48
DOIs
StatePublished - Dec 3 2014

Keywords

  • 2S seed storage albumin
  • 7S seed storage globulin
  • food allergy
  • mass spectrometry
  • tree nut
  • walnut

ASJC Scopus subject areas

  • Chemistry(all)
  • Agricultural and Biological Sciences(all)

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    Downs, M. L., Semic-Jusufagic, A., Simpson, A., Bartra, J., Fernandez-Rivas, M., Rigby, N. M., Taylor, S. L., Baumert, J. L., & Mills, E. N. C. (2014). Characterization of low molecular weight allergens from English walnut (Juglans regia). Journal of Agricultural and Food Chemistry, 62(48), 11767-11775. https://doi.org/10.1021/jf504672m