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Gradient centrifugation - (Dec/23/2015 )



I loaded a protein extract on glycerol gradient (10-50%) and spun at 55000 rpm for 2 hrs. I could see my protein of interest running in 5th fraction. I want to know the molecular weight of that protein mixture. Any Idea how to do that?


After asking Dr. google, I found out that we need to calculate sedimentation coefficient using known protein and then convert that into the molecular weight for unknown protein. Still I am not able to figure that outsad.png


If anybody has done these kind of experiment. Please help me with your experience.




you can also do it by running known proteins in the same tube and plot it out (sedimentation coefficient may be more accurate but you will also need to determine the glycerol concentration (or density) where each protein migrates).