How do I perform an Acetone Precipitation for concentrating and desalting protein samples?

The following protocol is suitable for concentrating and desalting protein samples for downstream applications such as 2D-PAGE:

• Add four volumes of ice-cold 100% acetone to the protein fraction and incubate for 15 minutes on ice
• Centrifuge for 10 minutes at 12,000 x g in a pre-cooled microcentrifuge at 4°C
• Discard the supernatant and air dry the pellet
• Resuspend the pellet in an appropriate sample buffer required for the downstream application

You will find this protocol also in the handbooks for QIAGEN's QProteome Protein Fractionation Kits.