The NativePAGE Invitrogen Bis-Tris Gel System is a pre-cast polyacrylamide mini gel system that provides a sensitive and high-resolution method for analyzing native membrane protein complexes, native soluble proteins, molecular mass estimations, and assessing purity of native proteins. It is based on the blue native polyacrylamide gel electrophoresis technique (BN PAGE) developed by Schagger and von Jagow.