Two-dimensional gel electrophoresis pattern (pH 6-11) and identification of water-soluble barley seed and malt proteins by mass spectrometry.
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.
Carlsberg Laboratory, Department of Chemistry, Copenhagen Valby, Denmark.
Kristian Sass
KS
Bak-Jensen
Sabrina
S
Laugesen
Peter
P
Roepstorff
Birte
B
Svensson
D002241:Carbohydrates / Q000737:chemistry; D002523:Edible Grain / Q000378:metabolism*; D015180:Electrophoresis, Gel, Two-Dimensional / Q000379:methods*; D006019:Glycolysis; D001467:Hordeum / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D013058:Mass Spectrometry / Q000379:methods*; D009584:Nitrogen / Q000737:chemistry; D010455:Peptides / Q000737:chemistry; D017510:Protein Folding; D017434:Protein Structure, Tertiary; D011506:Proteins / Q000737:chemistry; D012639:Seeds / Q000378:metabolism; D014867:Water / Q000737:chemistry*
D002241:Carbohydrates; D010455:Peptides; D011506:Proteins; D014867:Water; D009584:Nitrogen