The role of pH and membrane porosity in preparative electrophoresis.

The Gradiflow is a preparative electrophoresis apparatus, allowing fractionation based on a combination of size and charge of proteins in their native (unreduced) form. The preparative fractionation of two proteins of similar size and isoelectric point is demonstrated using the Gradiflow. A separation membrane of appropriate pore size was chosen and then fractionation was "fine tuned" by selecting an appropriate buffer pH to accentuate charge differences between the proteins of interest. Complete separation of mg quantities of bovine serum albumin and ovalbumin was achieved within 40 min.