Cetyltrimethylammonium bromide discontinuous gel electrophoresis: Mr-based separation of proteins with retention of enzymatic activity.

A discontinuous polyacrylamide and agarose gel electrophoresis system is presented here which allows the fine separation of proteins based on molecular weight with the concomitant retention of native enzymatic activity. This system, referred to as the CAT gel, uses the cationic detergent cetyltrimethylammonium bromide (CTAB) and includes a stacking gel based on the zwitterion arginine and the buffer N-tris(hydroxymethyl)-methylglycine. The CAT gel system allows specific enzyme histochemical detection and localization of proteins after gel electrophoresis. We present evidence that the CAT system stacked and separated a broad range of proteins into discrete bands which migrate as a linear function of log Mr. We have also assessed the effect of CTAB solubilization on the activity of several proteins and showed that some proteins separated by CAT electrophoresis maintain high levels of native enzymatic activity and may be detected histochemically in situ.