Abstract:

OBJECTIVE: To explore the sources and control methods of non-sample bands in the protein SDS-polyacrylamide gel electrophoresis. METHODS：The sample loading buffer，and its different component parts without protein sample were directly added to the gel and electrophoresed to identify the non-sample bands. Impact on non-sample bands of gradient concentrations of reducing agent and glycerol in the buffer were also assessed. The effective methods for removing the non-sample bands were further verified by pretreatment comb for preparation gel. Finally，method for reducing non-sample bands was tested by SDS-PAGE electrophoresis of protein of Vibrio parahaemolyticus. RESULTS：Non-sample bands appeared as long as the reducing agent and glycerol were both present in the buffer solution with comb pretreated by ordinary commercially available detergents，but the intensity of the bands showed no significant dose relationship with the concentration of reducing agent or glycerol. Treating the comb with 8 mol/L urea liquid，the non-sample bands showed weakening or even disappeared. CONCLUSION：Non-sample bands were caused by pollution of the comb. Treating the comb with a strong protein dissolving agent，such as 8 mol/L urea may be useful to reduce as eliminate non-sample bands.

Key words: SDS-PAGE, non-sample bands, sample loading buffer, pollution