Changes in the composition and size distribution of endosperm proteins from bug-damaged wheats

D. Sivri, Ian L. Betey, Ian L. Batey, Daniel Skylas, Laila Daqiq, C W Wrigley

Research output: Contribution to journalArticlepeer-review

19 Citations (Scopus)

Abstract

In this study, grain that had been damaged by the bug Eurygaster spp. and/or Aelia spp., plus some undamaged grain, was selected from hard red winter (HRW) wheat. The changes in endosperm proteins were determined by 2-dimensional (2-D) electrophoresis and size-exclusion high-performance liquid chromatography (SE-HPLC). Although some new protein spots and a slight decrease in the staining intensities of some polypeptides were observed in the 2-D map of the bug-damaged sample, other parts of the gels were similar to the sound (control) sample in terms of relative mobilities and intensities of the polypeptide spots. The major difference between bug-damaged and control samples was that a group of polypeptides, presumably HMW-glutenins, shifted to a more basic region of the map. The SE-HPLC patterns of the total proteins extracted from control and bug-damaged samples in SDS-buffer showed that they differed in the size distribution of the polymeric glutenin protein and in their glutenin/gliadin ratios. The solubility of proteins in SDS buffer was greater in the bug-damaged sample. The 'unextractable' polymeric protein (only extractable in SDS-buffer after sonication) (UPP %) was significantly lower in the bug-damaged sample than in the control. The results of 2-D analysis and the decline in the quantity of unextractable proteins in SDS buffer suggest that bug-protease causes dough weakening by degradation of polymeric glutenin, presumably by hydrolysis, and possibly other mechanisms that affect the aggregation of the gluten molecules.
Original languageEnglish
Pages (from-to)477-483
Number of pages7
JournalCrop and Pasture Science
Volume55
Issue number4
DOIs
Publication statusPublished - 2004
Externally publishedYes

Keywords

  • Bug protease
  • Gluten depolymerisation

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