I'm currently doing a Western blot for a protein with a MW of 52 kDa, but when I do my Western blot, the band shows up somewhere below the 70 Kda, but higher than 55 kDa.
So it makes me worry a little bit. I've read some forums about the inaccuracy of the pre-stained MW markers and that they can be off by 10 to 30 kDa, but I would like to confirm this data.
I believe you are using prestained molecular weight markers from a reliable source and whatever mobility you see for a particular protein is accurate for a defined percentage of gel.
Point to be remembered that electrophoretic mobility is not a linear fit when plotted mol wt (kDa) against electrophoretic mobilty (cm), where as it is a logarithmic fit for log [MW] against electrophoretic mobility (cm).
For further reading I would suggest you to consult the link I am sharing.
http://www.ruf.rice.edu/~bioslabs/studies/sds-page/mw.html
Hope that helps.
I believe you are using prestained molecular weight markers from a reliable source and whatever mobility you see for a particular protein is accurate for a defined percentage of gel.
Point to be remembered that electrophoretic mobility is not a linear fit when plotted mol wt (kDa) against electrophoretic mobilty (cm), where as it is a logarithmic fit for log [MW] against electrophoretic mobility (cm).
For further reading I would suggest you to consult the link I am sharing.
http://www.ruf.rice.edu/~bioslabs/studies/sds-page/mw.html
Hope that helps.
I'm using pre-stained protein ladder from Fermentas # SM0671, but after checking my gel and blot i realized that two of the bands were not well resolved and were merged together so my protein was in the right size. But I have read the information you sent me and it seems pretty accurate, and my conclusion is that prestained protein ladders are not as reliable for size as the unstained :P.
Thank you very much Amritlal!.
Best regards
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