Bradford and triton lysis buffer - (Jul/04/2011 )

I'm a little late to the party but will offer help to others planning similar assays.

Coomassie blue (Bradford reagent) reacts with Triton x-100 and other detergents, so will cause significant interference. In many cases, the interference is high enough to destroy any hope of building a reliable standard curve, which is critical for protein quantitation.

To check at which concentration of Triton x-100 in a lysis buffer is suitable for a Bradford assay, I ran a serial dilution of:

2%, 1%, 0.5%, 0.25%, 0.125%, 0.0625%, 0.03125%, 0.01562%, and 0% Triton x-100 in HBSS.

I found that loss of interference occurred near 0.0625%, which could explain why many lysis buffer recipes call for 0.05% Triton x-100 - I gather such buffers were designed to be Bradford compatible. In summary, I wouldn't exceed 0.05% if you want /need to use a Bradford assay.