CHAPS is a nondenaturing zwitterionic detergent for membrane biochemistry. Useful for solubilizing membrane proteins and breaking protein-protein interactions. CHAPS’ small micellar molecular weight (6,150; aggregation number = 10) and high critical micelle concentration (6-10 mM) allow it to be removed from samples by dialysis. It is also suitable for protein solubilization for isoelectric focusing and two-dimensional electrophoresis. CHAPS is commonly used for non-denaturing (without urea) IEF and has been shown to give excellent resolution of some subcellular preparations and plant proteins. Concentrations between 2-4% (w/v) are typically used in an IEF gel.