(3-[(3-Cholamidopropyl)-dimethyl-ammonio]-2-hydroxy-1-propane sulfonate)A nondenaturing zwitterionic detergent for solubilizing proteins. It has a more polar head group than CHAPS, giving it greater solubility. CHAPSO has a high Cmc (8mM) and does not denature membrane-bound proteins. It can solubilize the opiate receptor in a state exhibiting reversible binding of opiates.Ref.: W.F. Simonds, et al., Proc. Nat'l. Acad. Sci. USA, 77: 4-623 (1980).