[ Submit a Question, Answer or Critique]
From: Rebekah Healy
Date: 05 Feb 2004
Time: 18:03:36 -0500
Remote Name: 172.16.10.43
hey natasha! Coomassie is a dye that binds to proteins non-specifically, meaning it binds to virtually all proteins. The blue that you see is actually a result of the dye absorbing non-blue wavelengths of visible light while reflecting blue light. The intensity of the color change is directly proportional to the concentration of protein within the solution. Coomassie blue also becomes more acidic when it binds to the protein, another reason for the color change (it starts out brownish-red). See, it’s the anionic form of the dye that actually binds to the proteins (most likely thought to be the sulfonic acid groups within the dye. I found some sites that might help you out: the first one is a good explanation of what it is, how and why it works, and also gives a picture of the dye’s structure. The second one has good pictures of what it looks like when you use this dye in lab – in Biochem lab, we used this ALL the time to make sure we actually had protein in our products, haha! http://www.piercenet.com/files/coomass.pdf http://jchemed.chem.wisc.edu/JCESoft/CCA/CCA5/MAIN/2BIOCHEM/BIOCHEM1/COOMASSIE/THUMBS.HTM