Protein extraction is usually performed using organic solvents like acetone or trichloro-acetic acid. The organic solvents are responsible for increasing the protein-protein interaction by removing the solvation spheres around the proteins. As more and more proteins interact, they aggregate and hence precipitate down. For solubilizing the proteins, chaotropic agents Urea, thiourea and detergents such as CHAPS are used. The chaotropic agents and surfactants are responsible for denaturing the proteins, which further break their intermolecular and intramolecular interactions. Once these interactions are broken, the water molecules are able to solubilize the proteins much easily. The proteins are first separated from nucleic acids and membranes by suitable treatments and then precipitated from the solution by use of organic solvents. In certain cases, especially where membrane proteins are involved, their greater hydrophobicity prevent them from easy dissolution. Thio-urea in this aspect becomes extremely helpful, in terms of stabilizing the membrane proteins. In many cases, ionic detergents like SDS pose a problem in downstream processes like electrophoresis. Zwitter-ionic detergents such as CHAPS (3-((3-cholamidopropyl) dimethylamino)-1-propane sulfonate) are extremely useful in solubilization and are also compatible with electrophoresis. Addition of DTT (dithiothreitol) enhances solubilization by reducing the disulfide linkages. Even though acetone and TCA are effective precipitants, care should be taken during removal of excess solvents from the precipitants. The sample should also not be extremely dry, or else, solubiliziation in appropriate buffer becomes an issue.