Two-dimensional gel electrophoresis pattern (pH 6-11) and identification of water-soluble barley seed and malt proteins by mass spectrometry

Proteomics. 2004 Mar;4(3):728-42. doi: 10.1002/pmic.200300615.

Abstract

A protocol was established for two-dimensional gel electrophoresis (2-DE) of barley seed and malt proteins in the pH range of 6-11. Proteins extracted from flour in a low-salt buffer were focused after cup-loading onto IPG strips. Successful separation in the second dimension was achieved using gradient gels in a horizontal SDS-PAGE system. Silver staining of gels visualized around 380 (seed) and 500 (malt) spots. Thirty-seven different proteins from seeds were identified in 60 spots, among these 46 were visualized also in the malt 2-D pattern. Proteins were identified by peptide mass fingerprinting and by tandem MS sequencing after in-gel digestion by trypsin. In addition, the N-terminal sequence of 10 different proteins from 11 spots was determined after electroblotting to a polyvinylidene difluoride (PVDF) membrane. Five identified proteins (in 9 spots) are involved in glycolysis, 12 in defence against pathogens (21 spots), 4 in storage, folding, and synthesis of proteins, and in nitrogen metabolism (5 spots), 6 in carbohydrate metabolism (11 spots), and 4 in stress and detoxification (9 spots). Six proteins (7 spots) were not grouped in these categories, and 3 were not ascribed a function. The presented 2-D patterns and identifications will be used to describe proteome differences between cultivars and changes during malting.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Carbohydrates / chemistry
  • Edible Grain / metabolism*
  • Electrophoresis, Gel, Two-Dimensional / methods*
  • Glycolysis
  • Hordeum / metabolism*
  • Hydrogen-Ion Concentration
  • Mass Spectrometry / methods*
  • Nitrogen / chemistry
  • Peptides / chemistry
  • Protein Folding
  • Protein Structure, Tertiary
  • Proteins / chemistry
  • Seeds / metabolism
  • Water / chemistry*

Substances

  • Carbohydrates
  • Peptides
  • Proteins
  • Water
  • Nitrogen