Protein Extraction and Precipitation

Efficient extraction of proteins is a key factor for successful proteomic experiments. Samples used for proteomic investigations may be in form of protein solution, e.g. body fluids, cell suspension such as cell cultures or solid samples such as tissues. Each type of sample, i.e. hydrophobic v. hydrophilic, will require different approach to achieve the best yield of extraction. Final volume of extracted proteins will depend on technique used and amount of initial material. In many instances sample volume needs to be reduced for which various techniques are available. Simple concentration in vacuum will cause that all impurities and salts will be concurrently concentrated and may interfere with further steps of sample fractionation. Therefore, protein precipitation techniques are discussed.