Electrophoresis on uncrosslinked polyacrylamide: Molecular sieving and its potential applications

Abstract

Abstract Uncrosslinked polyacrylamide, a viscous liquid, provides a molecular sieving effect in electrophoresis qualitatively the same as that of crosslinked gels. This finding confirms previous results by others using uncrosslinked polyacrylamide mixed with various gel matrices. It provides a sieving medium constituted by an entirely and necessarily random association of inert fibers, as stipulated for interpretation of migration by the Ogston theory. Ferguson plots of several proteins in uncrosslinked polyacrylamide exhibit Y o values smaller and less divergent from one another than in 5 % crosslinked gels, suggesting a curvature of the Ferguson plots of crosslinked polyacrylamide gels at low %T. If linearity of these plots at low %T, 0 %C could be demonstrated, a means would be found to determine accurate values of free mobility by their linear extrapolation to 0 gel concentration. Potentially, uncrosslinked polyacrylamide at low concentrations may provide a tool for the analytical sieving of subcellular particles. However, electrophoresis in uncrosslinked polyacrylamide at concentrations of less than 10 % is perturbed by convection, and thus these potential applications will depend on combining it with a suitable anticonvective device.