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SDS-PAGE question - seperate protein (Oct/01/2004 )

Hi There,

I am new here.
I got a problem with seperating proteins. is that possible to seperate alpha-S2-casein from alpha-S1-casein with 10% gel?
because alpha-S1-casein(bovine milk) standard I bought from aldrich contains small amount of alpha-S2-casein, Molecular weight of S1 is 24529Da, and MW for S2 is 26019Da. their MW are very close. I tried one time by applying 200V on it, but it failed.
Is there any way to seperate them on 10% 1-D SDS-PAGE?
Can I just slow down the current applied to do it? If it is impossible, should I try 12% gel?

Thanks for any suggestion to me!

Thanks a lot.



Better try 12% gel; also, use lower voltage- say 80 or 100 V.

good luck


try 10% gels, and low voltage 50-60, I use that to separate a 27and 30 KDs respectively and it worked fine


12% is a better percentage. in one of my trainings, the boss told me that for better separations, polymerization should be done overnight and entrance of proteins in the gel until the separating gel should be at 80mA continious.

i've never let polymerization overnight, but for separation of close mw proteins, this 50mA-protocol was great !!