Protocol Online logo
Top : Forum Archives: : General Lab Techniques

Question: What purpose does bromophenol blue serve in my protein isolation? - protein isolation (Feb/06/2008 )

I am beginning a new project and have received a protein isolation protocol from a different lab. I would like to use the Lowry method to quantify the protein, but I am concerned that the bromophenol blue in this protocol might interfere with the absorbance. My questions are:
1) Will the bromophenol blue interfere if using the Lowry method (I think I will purchase Biorad's DC Assay, based on the lowry method)?
2) What is the function of bromophenol blue in protein isolation?
This is the 2x protein isolation buffer recipe:
i. 6mL 1M Tris (pH=8)
ii. 1.0 g DTT
iii. 10mL 2% SDS
iv. 15g Sucrose
v. 0.06g E-Aminocaproic Acid
vi. 0.018g Benzamidine
vii. 0.010g Bromophenol Blue


-Kalisz Lab-

It looks like SDS-PAGE sample (lysis) buffer.


as k.b. said, it is sds-page sample buffer. the bromphenol blue will interfere with the protein determination. but so will sds and dtt and, to a lesser extent, tris (although you may be able to blank for these).

what is it that you want to do with the protein you isolate with this solution?


The bromophenol blue is a dye which migrates with the electrophoretic front due to its high ionic nature and small Mr.