Amount of Poly didc to use in EMSA? - (Aug/22/2007 )

Hi all:

I've been running EMSAs on purified NF-kB subunits and my protocol tells me to add 600 nanograms of poly didc to each well (total well size is 6 ul : 3 ul binding buffer+1ul of hot probe + 2 ul of proteins)

i read in promegas protocol that poly didc is not even necessary for purified proteins, or at most add 50-100 nanograms. Would adding 600 nanograms of poly didc affect my results?

thanks for you help

it's like blocking in Westerns; same idea. too much shouldn't hurt anything, I don't think, for that application. purified or not, non-specific binding is not something you want