Rod shaped gel system

Commercial apparatuses of this type are available from e.g.. Desaga, Heidelberg, FRG Savant Instruments, Hicksville NY, USA or BioRad Laboratories, Richmond, CA, USA. Many types of the apparatus have been described in the literature [96-99]. 

Before electrophoresis the gel tubes (usual dimensions are 50-100 X 5 mm) are placed into a rack (vertically) with the lower ends blinded with rubber caps or by plastic rods. The solutions needed are equilibrated at room temperature, the solutions for the lower gel are mixed and pipetted into the tube (to give a gel height of about 50 mm). The surface is carefully overlayed with water (the surface should be smooth and equal, not disturbed by addition of the overlaying water) and permitted to polymerize for half an hour. If the polymerization is too fast, the concentration of persulphate should be lowered, as otherwise the gel would be inhomogenous and 

001% Bromphenol blue (alkaline system) or 2 ml of 0.005% Pyronine (acidic system) are added to the upper reservoir. These dyes then form the zone of tracking dye in the electrophoretogram. A detailed study on gel polymerization kinetics has been published [100,101]. 

After the tracking dye has migrated close to the bottom (about 1 cm from the end of the gel), electrophoresis is stopped, tubes dismounted and gels prepared for 

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