Hi Alex, Your loading dye is bromophenol blue which does not interact with proteins and forms your dye front during SDS-PAGE. During staining, you are exchanging the buffer/solution your gel is in from the small volume of SDS containing running buffer in your gel to the large volume of Coomassie Blue staining solution. Essentially you are diluting away the SDS and replacing it with Coomassie Blue solution. Also, you are replacing your Tris-glycine SDS solution with a Methanol-Acetic Acid Coomassie Blue solution so the nature of the solution changes the nature of the SDS interaction with the protein as well.
HTH, Chris — Christopher L. Colbert, Ph.D. Associate Professor Department of Chemistry and Biochemistry North Dakota State University P.O. Box 6050 Dept. 2710 Fargo, ND 58108-6050 PH: (701) 231-7946 FAX: (701) 231-8324 From: CCP4 bulletin board <CCP4BB@JISCMAIL.AC.UK<mailto:CCP4BB@JISCMAIL.AC.UK>> on behalf of Alex Lee <alexlee198...@gmail.com<mailto:alexlee198...@gmail.com>> Reply-To: Alex Lee <alexlee198...@gmail.com<mailto:alexlee198...@gmail.com>> Date: Thursday, October 4, 2018 at 8:24 PM To: "CCP4BB@JISCMAIL.AC.UK<mailto:CCP4BB@JISCMAIL.AC.UK>" <CCP4BB@JISCMAIL.AC.UK<mailto:CCP4BB@JISCMAIL.AC.UK>> Subject: [ccp4bb] [Offtopic] Protein stain in Coomassie Blue dyes Dear All, I am thinking that in an SDS-PAGE experiment, if protein samples are boiled in SDS containing loading dye, and supposedly SDS interacts with proteins, why the Coomassie Blue dyes could still interact with and stain the proteins? I am thinking SDS is covering the proteins, making no room for the Coomassie Blue dyes interaction. I'd appreciate it if any input from this forum. Alex ________________________________ To unsubscribe from the CCP4BB list, click the following link: https://www.jiscmail.ac.uk/cgi-bin/webadmin?SUBED1=CCP4BB&A=1 ######################################################################## To unsubscribe from the CCP4BB list, click the following link: https://www.jiscmail.ac.uk/cgi-bin/webadmin?SUBED1=CCP4BB&A=1
