Written by Merel Dagher (PEACE Advisor)
After we get our desired proteins, how can we test to see if the protein we want to purify is in the sample of proteins? (More than one answer choice may be correct)
a. perform a colorimetric assay
b. perform a radiochemical assay
c. perform an immunological assay
d. perform a Biuret test
e. use the Bradford method
a. perform a colorimetric assay
b. perform a radiochemical assay
c. perform an immunological assay
d. perform a Biuret test
e. use the Bradford method
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The correct answers are a, b, and c. Performing any of those options can show you whether you have your desired protein. However for options d and e, these will tell you how much TOTAL protein you have in your sample, and not detect any specific protein. The protein test is part of the Lowry method for total protein determination and uses copper ions to form a pink/violet biuret complex. The Bradford method is another way of detecting total protein which uses Coomassie Brilliant Blue G-250 to create a protein-dye complex that shows a dark blue color.