use of BSA in EMSA supershifts

gc genecutl at
Wed Sep 7 19:35:28 EST 1994

In article <34kh9d$7jm at>, <grgmj at> wrote:

< Hi - I'm currently trying to supershift an E2A gene product from a nuclear
< extract and having problems.  The Ab is from NBS Biologicals and has been well
< used in the literature but the publication of methods seems sparing. I've 
< noticed the use of BSA in reactions "to top up protein amounts". Is this
< as some sort of blocking agent a la Westerns or is there some other function
< I'm missing? I'm going to try it out anyway tonite and I'll let you all know
< if it miraculously works. If anyone has handy hints about these assays in
< general I'd love to know! Thanks.

I think the main reason for including BSA is that the amounts of protein
used in band-shift reactions are very small.  Because of this loss
of protein at the liquid-air and liquid-eppendorf boundaries become 
significant.  Adding BSA does act like a blocking agent, in this case its
blocking the aformentioned liquid boundary regions that can cause protein


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