Horizontal gel electrophoresis with sample volumes up to 1.5 mL, using a discontinuous buffer system and automated apparatus.

Horizontal gel electrophoresis has previously suffered from lack of an instrumental design that would allow for application of large sample volumes. A recently introduced commercial apparatus (HPGE-1000, LabIntelligence) remedies that problem in application to gel electrophoresis with intermittent scanning of fluorescence by using the concentrator module of that apparatus as a stacking gel reservoir. By using this technique and a 3 mL stacking gel, protein samples of up to 1.5 mL yield bands in the horizontal resolving gel that are independent of sample volume in their width, area and migration rate. A remaining procedural problem relates to the apparent nonsimultaneity of dye and protein entrance into the resolving gel, which necessitates peak characterization by absolute rather than relative mobilities.