One-dimensional electrophoresis using nondenaturing conditions.

Nondenaturing or "native" electrophoresis (i.e., electrophoresis in the absence of denaturants such as detergents and urea) is an often-overlooked technique for determining the native size, subunit structure, and optimal separation of a protein. Because mobility depends on the size, shape, and intrinsic charge of the protein, nondenaturing electrophoresis provides a set of separation parameters distinctly different from mainly size-dependent denaturing sodium dodecyl sulfate-polyacrylamide gel electrophoresis and charge-dependent isoelectric focusing. Two protocols are presented in this unit. Continuous PAGE is highly flexible, permitting cationic and anionic electrophoresis over a full range of pH. The discontinuous procedure is limited to proteins negatively charged at neutral pH but provides high resolution for accurate size calibration.