BCA Assay and SDS-PAGE Gels Do Not Agree - (Aug/18/2010 )

Hello All.

I am running a protein on a BCA Protein Assay (Pierce) and getting good results. I loaded 20 uL of the undiluted sample (approx 2ug/uL according to BCA, so 40 ug)on a denaturing 4-20% Novex SDS-PAGE gel with 5 uL sample buffer and see absolutely nothing. Any suggestions/insight would be greatly appreciated.

I dunno what concentration sample buffer you are using, but usually I use a 1:1 volume ratio of sample buffer to diluted/undiluted sample

And what do you mean by "See absolutely nothing"? You mean you don't see the protein lanes running down or something?

Have you fixed your gel before staining? What kind of staining have you used?