Aug 26, 2020
COOMASSIE COLLOIDAL STAIN - CHEM 584
- 1Brigham Young University
Protocol Citation: Ken Christensen 2020. COOMASSIE COLLOIDAL STAIN - CHEM 584. protocols.io https://dx.doi.org/10.17504/protocols.io.bkcqksvw
License: This is an open access protocol distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited
Protocol status: In development
We are still developing and optimizing this protocol
Created: August 26, 2020
Last Modified: September 16, 2021
Protocol Integer ID: 41072
Abstract
Staining polyacrylamide gels using a colloidal Coomassie Blue stain. Adapted from a JoVE article.
Wash gel with ~50 mL ddH2O 3x for ~00:10:00 for each wash on a shaker
NOTE: insufficient washing causes poor sensitivity because the remaining SDS on the gels disturbs the bounding of the dye to the protein
Shake the colloidal Coomassie solution before use to disperse particles evenly.
Incubate the gels with the Coomassie solution by agitation on a shaker up to 12:00:00 . This staining generates marginal background so you can observe the staining progress.
Note: after 10 minutes you should see some protein bands appearing, within 2 hours of incubation about 80% maximum staining is completed. For nearly maximum sensitivity, an overnight incubation is recommended. In some cases, when the amount of protein to be stained is large, the solution turns a bright blue color. If this happens, you should refresh the staining solution as necessary.
After staining, remove the Coomassie solution and rinse the gels twice with ddH2O.
Note: you can reuse the staining solution as long as particles still remain, otherwise discard it appropriately.
Remove any dye particles from the staining dish with a lint-free paper towel and destain for up to 01:00:00 in ddH2O or a Coomassie destain solution (10% (v/v) 96% ethanol, 2% (v/v) orthophosphoric acid 85% in ddH2O.)
Finally rinse the gels twice with ddH2O: the gels will reach their original thickness (the alcohol-acid media makes the gels shrink). Neutralization in water also enhances the Coomassie stain’s color intensity.
You can record your gel using the gel documentation system or scan it on the Licor using the 680/700 nm channel.