Improvements of isoelectric focusing in agarose for direct tissue isoelectric focusing

Abstract
Improvements of isoelectric focusing (IEF) in agarose are described that result in consistently obtaining broad, linear pH gradients in the range pH 4 to 9.2 at equilibrium. Cathodic drift has been reduced by the use of a blend of commercial carrier ampholytes and by incorporating lysine and arginine in the catholyte as spacers. Resolution has also been enhanced by the use of thin gels, supplemented with sorbitol and glycerol. In addition, a comparison of two agarose preparations for isoelectric focusing was performed using two commercial carrier ampholytes. To minimise background staining, Triton complexes were removed by modification of the fixing and clearing procedures. These modifications to IEF in agarose are being applied to direct tissue isoelectric focusing (DTIF) of normal and diseased human skeletal muscle.