High-performance sodium dodecyl sulfate polyacrylamide gel capillary electrophoresis of peptides and proteins

High-performance capillary sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) has been developed for the separation and molecular weight (MW) determination of peptides and proteins. In this work, acrylamide was polymerized in fused-silica capillaries of 75 microns I.D. and 10 or 20 cm length. On-line UV detection was employed by placing the capillary in the optical path of the detector. Rapid separations of myoglobin fragments and of a mixture of standard proteins were demonstrated with efficiencies of the order of 40,000 plates for a column, 20 cm in length. Linear plots of log MW vs. mobility for the SDS protein complexes were observed. Variation in the percentage monomer composition (% T) of the polyacrylamide yielded the expected common intercept of log mobility vs. % T, confirming the size separation mechanism in the gel capillaries. The separation of the A and B chains of insulin with a 10-cm column in less than 10 min was also demonstrated.