Proteinextraction for 2D-PAGE

Has anyone experience in extracting protein for 2D-PAGE?

I have tried several protocolls, but there is still a lot of horizontal streaking:

  • Lyophilisation of worms
  • Sonification in 8 M Urea, 2% CHAPS, 50 mM DTT and protease inhibitors
  • Ultracentrifugation
    • IEF

When I precipitate protein (MeOH/chloroform) I don`t get better results.

I would be thankful for any help!