Electrophoretic mobilities of the complexes between sodium dodecyl sulfate and various peptides or proteins determined by free solution electrophoresis using coated capillaries

Electrophoretic mobilities of various proteins or peptides complexed with sodium dodecyl sulfate (SDS) were determined by free solution capillary electrophoresis. The complexes formed between SDS and protein polypeptide showed electrophoretic mobilities virtually insensitive to the protein molecular weight. On the other hand, scattered and larger negative electrophoretic mobilities were observed for peptides of molecular weights less than 10000. Mobility differences as small as 0.3-3% among the three differently modified derivatives of bovine serum albumin could also be successfully determined due to the high resolving power of capillary electrophoresis.