low molecular weight proteins on SDS-PAGE - (May/29/2006 )

Hi, I used to do 2dimensional SDS-PAGE but recently facing a problem in resolving low molecular weight proteins. I used to run 12%SDS-PAGE (for 2nd dimension) and proteins below 25kd are getting stacked at the bottom of the gel with tracking dye. i am used to run my gels at constant voltage at 200 V. Earlier I was not facing this problem. I have checked my polyacrylamide mixture (30%), there is no problem in that. Is anybody there, who can suggest me to overcome my problem ?

hi sanjeev
why dont you try a sds tricine gel for the second dimension.
tricine page can resolve up to 500 da mw proteins.

good luck
gaganjot