CHAPS is a zwitterionic surfactant used in the laboratory to solubilize biological macromolecules such as proteins. It may be synthesized from cholic acid and is zwitterionic due to its quaternary ammonium and sulfonate groups; it is structurally similar to certain bile acids, such as taurodeoxycholic acid and taurochenodeoxycholic acid. It is used as a non-denaturing solvent in the process of protein purification and is especially useful in purifying membrane proteins, which are often sparingly soluble or insoluble in aqueous solution due to their native hydrophobicity.