What is the Difference Between Coomassie and Silver Staining

The key difference between Coomassie and silver staining is that coomassie staining is a protein staining technique that uses a coomassie brilliant blue stain, while sliver staining is a protein staining technique that uses a silver stain.

Protein separation and identification are critical steps in proteome analysis. They need high-resolution protein characterization after gel electrophoresis. There are numerous staining techniques that include different stains such as anionic dyes (coomassie brilliant blue), metal cations (imidazole-zinc), silver stain and fluorescent dyes, etc. Sometimes, radioactive probes can also be used. The choice of the staining technique depends on the simplicity, availability of imaging equipment in the laboratory, etc.

CONTENTS

1. Overview and Key Difference
2. What is Coomassie Staining
3. What is Silver Staining
4. Similarities – Coomassie and Silver Staining
5. Coomassie vs Silver Staining in Tabular Form
6. Summary – Coomassie vs Silver Staining

What is Coomassie Staining?

Coomassie staining is a protein staining technique that uses a coomassie brilliant blue stain. It is generally called the coomassie blue technique. Coomassie brilliant blue is the most popular anionic protein-dye. This stain normally stains almost all proteins with good quantitative linearity at medium sensitivity. Coomassie brilliant blue stain binds non-specifically to almost all proteins. There are two different coomassie brilliant blue stain variants: R-250 and G-250. R-250 offers shorter staining times, while G-250 is available in more sensitive and environmentally friendly formulations.

Coomassie dyes are very popular in mass spectrometry studies and protein identification studies. Moreover, bio-safe coomassie stain is a non-hazardous formulation of coomassie blue G-250 that is currently available in the market. The advantage of this formulation is it requires only water for rinsing and destaining. Bio-safe coomassie stain offers sensitivity equivalent to conventional coomassie blue G-250 but better than coomassie stain R-250. Furthermore, it has a simpler and quicker staining protocol than the conventional Coomassie blue G-250. The drawback of coomassie blue staining is that it is less sensitive compared to silver staining.  Coomassie blue staining is approximately 50-fold less sensitive than silver staining. However, due to its simplicity in binding, it is preferred in many studies.

What is Silver Staining?

Silver staining is a protein staining technique that uses a silver stain. Silver staining is used to stain both agarose and polyacrylamide gels. The silver staining of protein in agarose gels was first developed in 1973 by Kerenyi and Gallyas. Later, it was adapted for proteins in polyacrylamide gels that are used in SDS-PAGE. Currently, silver staining is also used for staining DNA or RNA. In order to stain the gels, the gels are incubated with silver nitrate solution in this method. Silver staining stains the sites where proteins are present from brown to black.

The intensity of the silver staining depends on the primary structure of the protein. Moreover, the cleanliness of the vessels used and the purity of reagents can also influence the quality of silver staining. However, the drawback of silver staining is that it is unable to detect all proteins, especially glycoproteins and proteins with large modified groups attached to their side chains.

What are the Similarities Between Coomassie and Silver Staining?

• Coomassie and silver staining are two techniques used in protein staining.
• They can stain both proteins and DNA.
• Both staining techniques have drawbacks.
• These techniques have similar steps, such as fixing, staining and destaining.

What is the Difference Between Coomassie and Silver Staining?

Coomassie staining is a protein staining technique that uses coomassie brilliant blue stain, while sliver staining is a protein staining technique that uses silver stain. Thus, this is the key difference between Coomassie and silver staining. Furthermore, Coomassie staining is less sensitive than silver staining.

The below infographic lists the differences between Coomassie and silver staining in tabular form for side by side comparison.

Summary – Coomassie vs Silver Staining

To visualize proteins, a protein-specific dye-binding or colour producing chemical reaction can be performed. This is called protein staining. Coomassie and silver staining are two techniques used in protein staining. Coomassie staining technique uses coomassie brilliant blue stain while sliver staining uses silver stain. So, this is the key difference between Coomassie and silver staining.

Reference:

1. R, Brunelle JL, Green. “Coomassie Blue Staining.” Methods in Enzymology, U.S. National Library of Medicine.
2. Chevallet, Mireille, et al. “Silver Staining of Proteins in Polyacrylamide Gels.” Nature Protocols, Nature Pub. Group, 2006.

Image Courtesy:

1. “SDS-PAGE Coomasie stained” By piemmea – Own work (CC BY-SA 3.0) via Commons Wikimedia
2. “PAGE AgStain Microsat” By ParinoidMarvin – Own work (CC BY-SA 3.0) via Commons Wikimedia