Removal of nonionic detergent from proteins fractionated by electrofocusing

The nonionic detergent Nonipol TD 12 (an alkyl polyoxyethylene alcohol) has been removed from solubilised proteins after their fractionation by electrofocusing. Following electrofocusing in nonionic detergent an anionic or cationic detergent was added to the focussing medium and the focusing was allowed to continue. The ionic detergent formed mixed micelles with the nonionic detergent. Thus charged, the mixed micelles migrated to either electrode, removing nonionic detergent from the fractionated proteins. Applying this technique to an adipose tissue preparation, detergent-inhibited activity of a lipolytic enzyme was restored and the binding of adenosine 3':5'-cyclic monophosphate (cyclic AMP) to a protein kinase was increased.