Low-tech electrophoresis, small but beautiful, and effective: Electrophoretic titration curves of proteins

Migration across a stationary pH gradient results in the electrophoretic ti tration of a protein's dissociable groups. From the resulting curves, some properties of the protein may be derived, including overall amino acid comp osition and type of mutation between polymorphic variants, as well as range of stability or, for enzymes, of catalytic activity. Analysis with this te chnique is a stringent purity criterion; other applications allow the study of interacting systems and the planning of chromatographic fractionations based on differences in surface charge.