Electrophoresis Time Not Optimized for Target Protein (Western Blot (Bands at Wrong MW))

Question

Accepted Answer

Protein bands do not align with expected molecular weight markers, with systematic upward or downward shifts affecting all bands uniformly. Pre-staining reveals migration issues before antibody detection. Common causes: 1) Running time and voltage combination not calibrated for specific gel composition and protein size range 2) Manufacturer instructions followed without adjustment for specific target protein characteristics 3) Lack of real-time monitoring of ladder marker separation during electrophoresis 4) Running parameters optimized for different protein size range than target of interest Solutions: 1) Run gel at 100-150V for 1-2 hours as starting point, adjusting based on target protein molecular weight 2) Frequently monitor ladder marker separation, stopping when target protein size range shows adequate resolution 3) Use pre-chilled electrophoresis buffer to maintain consistent gel temperature during run 4) Perform Coomassie blue staining of membrane after transfer to verify proper band positions before immunostaining 5) Document optimal running times for specific protein targets to establish laboratory-specific protocols