Anomalous behavior of certain poliovirus polypeptides during SDS-gel electrophoresis.

Urea is shown to be a useful additive to sodium dodecyl sulfate gels prior to electrophoresis and offers an alternative means for the resolution of some SDS-protein complexes. Two types of effect are described, one of which causes increases in the relative mobilities of certain polypeptides found in poliovirus-infected cells. It is postulated that urea plus SDS is able to achieve a more complete denaturation of some polypeptides, which leads to faster electrophoretic mobilities. The molecular weight estimations for such proteins in these conditions are therefore lower than those determined in the presence of SDS alone. A second effect of some urea solutions is to cause the multiple banding of the structural polypeptide VP3 when included in gels at high concentrations. This effect is variable and appears to be unrelated to the presence of cyanate ions.