Blurred low molecular weight bands in SDS-PAGE - Need your help (Aug/24/2009 )
I cast and run 12% SDS-PAGE gels for plant protein extracts. Low molecular weight proteins bands of my gels are always blurred while the high MW bands appear fine. This effect is common for pre-stained MW markers too.
I'm wondering whether my gels are bad. I always allow gels to polymerize overnight at room temperature. Could this be a problem with insufficient amount of TEMED and/or ammonium persulfate?
I greatly appreciate your suggestions and comments.
no. it is just the nature of electrophoresis (it may also be caused by insufficient stacking, buffers being "off",...)
there are a couple of ways to combat this.
one is to use a gradient gel (5-15%, 10-20%, 10-15%,...).
another is to add urea to the formula.
i prefer gradients.