How does Coomassie Blue stain the proteins in the gel?

The Coomassie dyes (R-250 and G-250) bind to proteins through ionic interactions between dye sulfonic acid groups and positive protein amine groups as well as through Van der Waals attractions. Solutions of the dye, dark blue black at pH 7, turn a clear tan upon acidification. …

What does a Coomassie stain show?

Coomassie Blue stain is used to stain the protein bands in polyacrylamide gels. This reagent will stain the proteins without staining the gel, so it is not necessary to destain the gel in order to see the protein bands.

Does Coomassie Blue stain all proteins?

The most common used protein stain is Coomassie Blue staining, which is based on the binding of Coomassie Brilliant Blue, which binds non-specifically to virtually all proteins. In addition, staining may be too intense in some cases, and partial destaining may be required to visualize closely migrating proteins.

How does Coomassie stain proteins on a SDS-PAGE gel?

In acidic conditions, Coomassie dye binds to basic and hydrophobic residues of proteins, changing in color from a dull reddish-brown to intense blue. An initial water wash step is necessary to remove residual SDS, which interferes with dye binding.

What does Coomassie blue stain bind to?

In acidic conditions, Coomassie dye primarily binds basic amino acids (arginine, lysine and histidine).

What does Coomassie blue stain do?

Description. Coomassie blue dyes are a family of dyes commonly used to stain proteins in SDS-PAGE gels. The gels are soaked in dye, and excess stain is then eluted with a solvent (“destaining”). This treatment allows the visualization of proteins as blue bands on a clear background.

What is colloidal Coomassie?

Bio-Rad’s QC colloidal Coomassie stain is a ready-to-use single-bottle protein stain that does not require the mixing of any components or addition of any alcohols. It is a special formulation of Coomassie G-250 that provides maximum sensitivity with low background for a wide variety of acrylamide gel chemistries.

Why is Coomassie Blue a good stain for proteins?

When proteins bind to Coomassie blue in acid solution their positive charges suppress the protonation and a blue colour results. The binding of the dye to a protein causes a shift in the absorption maximum of the dye from 465 to 595 nm and it is the increase in absorbance at 595 nm that is monitored.

Which amino acids does Coomassie bind to?

How do you stain Coomassie?

Stain: Dissolve 0.4g of Coomassie blue R350 in 200 mL of 40% (v/v) methanol in water with stirring as needed. Filter the solution to remove any insoluble material. Add 200mL of 20% (v/v) acetic acid in water. The final concentration is 0.1% (w/v) Coomassie blue R350, 20% (v/v) methanol, and 10% (v/v) acetic acid.

How do you use a Coomassie stain?

Stain the mini-gel with enough Invitrogen™ SimplyBlue™ SafeStain (20-100 ml) to cover the gel. Stain for 1 hour at room temperature with gentle shaking. Bands will begin to develop within minutes. After incubation, discard the stain.

Can you Western blot a Coomassie stained gel?

The answer is yes: western blotting Coomassie-stained proteins can be done, but it’s not a simple or efficient process. As you know, there are two types of Coomassie stains – “classical” and “colloidal”. Proteins stained by one of these two methods will behave differently if you try to blot them afterwards.

How do you stain Coomassie blue gel?

Submerge the gel in enough Coomassie Blue staining solution so that the gel floats freely in the tray. Shake slowly on a laboratory shaker for 30 min – 2 h. The amount of time required to stain the gel depends on the thickness of the gel. A 0.75 mm thick gel will stain faster than a 1.5 mm gel and may be completely stained in 30 min.

Does Biobio-Rad offer Coomassie stains?

Bio-Rad offers Coomassie stains in three major formats. Coomassie blue dyes are a family of dyes commonly used to stain proteins in SDS-PAGE gels. The gels are soaked in dye, and excess stain is then eluted with a solvent (“destaining”). This treatment allows the visualization of proteins as blue bands on a clear background.

How much protein can be detected in a Coomassie stain?

3-10 microgram of protein can be detected usually within 5 minutes in Coomassie stains. With additional water-based de-staining, as little as 7 ng of protein (BSA) can be detected.

What is the best stain for Coomassie?

Bio-Safe™ Coomassie (161-0786) — Bio-Safe Coomassie Brilliant Blue G-250 stain is fast, simple, sensitive, and convenient. Coomassie Brilliant Blue R-250 (161-0436) — Coomassie Brilliant Blue R-250 staining solution is the fastest and easiest way to Coomassie-stain Criterion™ precast gels or other polyacrylamide protein gels.