Whether you just need a quick visual confirmation or require a highly-sensitive stain to detect low-abundance proteins, we offer a variety of easy-to-use, effective protein stains for both in-gel and on-membrane detection. Check out our comprehensive collection of stains including Coomassie dye-based, silver, fluorescent, tagged fusion protein stains and PTM protein gel stains.
Polyacrylamide gel stains
 Coomassie staining |  Silver staining |  Fluorescent protein staining | |
|---|---|---|---|
| Sensitivity | 5-25 ng | 0.25-0.5 ng | 0.25-0.5 ng |
| Mode of action | Coomassie dye binds to basic and hydrophobic residues of proteins through non-covalent interactions, changing from dull reddish-brown to intense blue. | Silver ions interact and bind with carboxylic acid groups (Asp and Glu), imidazole (His), sulfhydryls (Cys), and amines (Lys). Silver ions are reduced to metallic silver, resulting in brown-black color. | Most fluorescent stains bind non-covalently to proteins either through the polypeptide backbone or through interaction with the SDS coat around the proteins |
| Typical protocol time | 10-135 min | 30-120 min | 60 min |
| Detection | Visual | Visual | UV or blue/green-light transilluminators or imaging instruments with appropriate filters |
| Compatibility with downstream applications | MS and sequencing compatible, western blotting (only non-fixative methods) | Certain formulations are MS compatible | Most stains are MS compatible, western blotting |
| Advantages | Quick and simple staining protocols, inexpensive | Lowest detection limits not requiring specialized equipment | Broad linear dynamic range with low detection limits |
| Learn more | Learn more | Learn more |
Coomassie dye stains
Coomassie dyes (also referred to as Coomassie blue or Coomassie brilliant blue) are common dyes used for the visualization of proteins separated by protein gel electrophoresis. Coomassie based stains offer easy staining protocols and provides good quantitative linearity with good sensitivity. Coomassie based dyes do not permanently chemically modify the target proteins rather interact via non-covalent interactions. Because no chemical modification occurs, excised protein bands can be completely de-stained and the recovered proteins can be used for analysis by mass spectrometry or sequencing.
In acidic conditions, Coomassie binds to basic and hydrophobic residues of proteins, changing in color from a dull reddish-brown to intense blue. As with all staining methods, Coomassie staining detects some proteins better than others, based on the chemistry of action and differences in protein composition. Thus, Coomassie staining can detect as little as 8–10 ng per band for some proteins and 25 ng per band for most proteins.
Two forms of the dye exists- R-250 (R standing for the reddish tint) and G-250 (G standing for the greenish tint). Both variants offer the same relative sensitivity and easy detection. Coomassie G-250 (also known as colloidal Coomassie dye) offers a faster staining protocols and eliminates the need for de-staining.
Silver dye stains
Silver staining is the most sensitive colorimetric method for detecting total protein. The technique involves the deposition of metallic silver onto the surface of a gel at the locations of protein bands. Silver ions (from silver nitrate in the staining reagent) interact and bind with certain protein functional groups. The strongest interactions occur with carboxylic acid groups (Asp and Glu), imidazole (His), sulfhydryls (Cys), and amines (Lys). Various sensitizer and enhancer reagents are essential for controlling the specificity and efficiency of silver ion binding to proteins and effective conversion (development) of the bound silver to metallic silver. The development process is essentially the same as for photographic film: silver ions are reduced to metallic silver, resulting in a brown-black color.
Silver staining protocols require several steps, which are affected by reagent quality as well as incubation times and thickness of the gel. An advantage of commercially available silver staining kits is that the formulations and protocols are optimized and consistently manufactured, helping to maximize consistency of results from experiment to experiment. Kits with optimized protocols are robust and easy to use, detecting less than 0.5 ng of protein in typical gels.
Silver stains use either glutaraldehyde or formaldehyde as the enhancer. These reagents can cause chemical crosslinking of the proteins in the gel matrix, limiting compatibility with de-staining and elution methods for analysis by mass spectrometry (MS). Therefore, optimization of sensitivity vs. protein recoverability is critical when employing silver staining as part of an MS workflow.
Silver stain formulations can be made such that protein bands stain black, blue-brown, red, or yellow, depending on their charge and other characteristics. This is particularly useful for differentiating overlapping spots on 2D gels.
Fluorescent dye stains
Fluorescent stains offer high sensitivity combined with simple staining protocols. Majority of fluorescent stains offer sensitivities similar to that obtained with silver staining techniques and can be used as a good alternative to silver staining in 1D or 2D electrophoresis. Unlike silver stains, fluorescent stains require equipment for visualization. Typical stains can be viewed with a standard UV or blue/green-light trans illuminator or with imaging equipment equipped with the appropriate filters. Fluorescent protein gel stains offer linear quantitation ranges, with some stains reporting over three orders of magnitude.
Nitrocellulose and PVDF membrane stains
| Pierce Reversible Protein Stain Kit | Ponceau S Staining Solution | SYPRO Ruby Blot Stain | No-Stain Protein Labeling Reagent | |
|---|---|---|---|---|
| Detection | Colorimetric (blue) | Colorimetric (pink-reddish) | Fluorescence (Ex: 280 & 450 nm, Em: 618 nm) | Fluorescence (Ex: 488 nm, Em: 590 nm) |
| Min. protein detected | ~25-50 ng | ~250 ng | ~2-8 ng | ~20 ng |
| Staining time | ~15 min | ~5 min | ~60 min | ~10 min |
| Applications | Monitoring transfer efficiency, total protein normalization after western blotting | |||
| Destaining before immunodetection | Destaining required | Destaining required | Not required | Not required |
| Considerations | Not recommended for fluorescent western blot detection | PVDF staining fixative required | ||
| Cat. No. | 24580 (nitrocellulose) 24585 (PVDF) | A40000279 (500 mL) | S11791 (200 mL) | A44449 (40 reactions) A44717 (10 reactions) |
Total protein stains
Colorimetric stains
| Product | Limit of detection | Components (steps)* | Time required** | Mass spec. compatible | Staining agent |
|---|---|---|---|---|---|
| GelCode Blue Safe Protein Stain | 9 ng | 2 (5) | 2 hr 15 min | Yes | G-250 |
| GelCode Blue Stain Reagent | 8 ng | 1 (5) | 2 hr 15 min | Yes | G-250 |
| Imperial Protein Stain | 3 ng | 1 (5) | 2 hr 15 min | Yes | R-250 |
| Simply Blue Safe Stain | >7 ng | 1 (5) | 12 min microwave 3 hr standard | Yes | G-250 |
| PageBlue Protein Stain | 5 ng | 1 (5) | 30 min microwave 90 min standard | Yes | G-250 |
| Colloidal Blue Staining | < 10 ng | 1 (3) | 10 hr | G-250 | |
| Pierce Silver Stain for Mass Spec | 0.25 ng | 6 (17) | 1 hr 13 min | Yes | Metallic silver ions |
| Pierce Silver Stain Kit | 0.25 ng | 4 (15) | 2 hr 25 min | Metallic silver ions | |
| Pierce Color Silver Stain Kit | 0.1 ng | 4 (9) | 4 hr 5 min | Yes | |
| Pierce Zinc Reversible Stain Kit | 0.25 ng | 3 (4) | 14 min | Yes | |
| SilverXpress Silver Staining Kit | 0.86 ng | 5 (13) | 2 hr | Metallic silver ions | |
| SilverQuest Silver Staining Kit | 0.3 ng | 7 (8) | 1 hr 30 min | Yes | Metallic silver ions |
| Pierce Reversible Protein Stain Kit for Nitrocellulose membranes | 25-50 ng | 3 (5) | 15 min | ||
| Pierce Reversible Protein Stain Kit for PVDF Membranes | 25-50 ng | 4 (8) | 15 min | ||
| Ponceau S Staining Solution | ~250 ng | 1 (3) | 15 min | Ponceau S |
Fluorescent stains
| Product | Limit of detection | Components (steps)* | Time required** | Mass spec. compatible | Excitation and emission maxima |
|---|---|---|---|---|---|
| SYPRO Ruby | 0.25- 1 ng | 1 (3) | 90 min microwave 18 hr standard | Yes | Excitation: 280, 450nm Emission: 610 nm |
| SYPRO Orange | 4-8 ng | 1 (5) | ~1 hr | Excitation: 300, 470nm Emission: 570 nm | |
| SYPRO Red | 4-8 ng | 1 (5) | ~1 hr | Excitation: 300, 550nm Emission: 630nm | |
| SYPRO Tangerine | 1-4 ng | 1 (4) | ~1 hr | Yes | Excitation: 300, 490nm Emission: 640nm |
| SYPRO Ruby blot stain | 2-8 ng | 1 (4) | ~1 hr | Yes | Excitation: 280, 450nm Emission: 618nm |
| Coomassie Fluor Orange | 8 ng | 1 (4) | ~1 hr | Excitation: 300, 470nm Emission: 570nm | |
| Krypton Fluorescent Protein Stain | 0.25 ng | 1 (7) | 2 hr 40 min | Yes | Excitation: 520nm Emission: 580nm |
*Some products require additional reagents to be supplied by user. The number of steps includes gel washes, solution changes, destaining steps, etc.
**Times include gel wash steps and all steps required for best sensitivity in a mini-gel. When less sensitivity is required, shorter staining and destaining times may be used with some protocols.
Functional group protein stains
| Product | Functional group | Limit of detection | Components (steps)* | Time required** | Detection method | Mass spec. compatible |
|---|---|---|---|---|---|---|
| Pro-Q Emerald 488 Glycoprotein Gel and Blot Stain Kit | Periodate-oxidized carbohydrate groups | 4 ng glycoprotein / band | 2 (13) | ~6 hrs | fluorescent | Yes |
| Pro-Q Emerald 300 Glycoprotein Gel and Blot Stain Kit | Periodate-oxidized carbohydrate groups | 0.5 ng glycoprotein / band | 2 (10) | ~5 hrs | UV | Yes |
| Pierce Glycoprotein Stain | Sialic acid and other oxidizable carbohydrate groups | 160 ng | 5 (11) | 2 hr 40 min | colorimetric | Not tested |
| Pro-Q Diamond Phosphoprotein Gel Stain | Phosphate groups attached to tyrosine, serine, or threonine residues | 1–16 ng phosphoprotein / band | 1 (5) | ~4-5 hrs | fluorescent | Not tested |
| Pro-Q Diamond Phosphoprotein Blot Stain Kit | Phosphate groups attached to tyrosine, serine, or threonine residues | 8-16 ng | 1 (6) | ~75 min | fluorescent | Yes |
| Lumio Green Detection Kit | Lumio, TC-tag | 1 pmole of a Lumio fusion protein | 3 (8) | Immediate | UV, fluorescent | Not tested |
| InVision™ His-tag In-gel Stain | 6X His-tag | ~0.5 picomole of a 6X His-tagged fusion protein | 2 (4) | <3 hrs | UV, fluorescent | Not tested |
| 6xHis Protein Tag Stain Kit | 6X His-tag | 200 ng | 4 (9) | 2 hr 20 min | UV, fluorescent | Not tested |
*Some products require additional reagents to be supplied by user. The number of steps includes multiple gel washes, solution changes, destaining steps, etc.
**Times include gel wash steps and all steps required for best sensitivity in a mini-gel. When less sensitivity is required, shorter staining and destaining times may be used with some protocols.
Polyacrylamide gel stains
| Coomassie staining | Silver staining | Fluorescent protein staining | |
|---|---|---|---|
| Sensitivity | 5-25 ng | 0.25-0.5 ng | 0.25-0.5 ng |
| Mode of action | Coomassie dye binds to basic and hydrophobic residues of proteins through non-covalent interactions, changing from dull reddish-brown to intense blue. | Silver ions interact and bind with carboxylic acid groups (Asp and Glu), imidazole (His), sulfhydryls (Cys), and amines (Lys). Silver ions are reduced to metallic silver, resulting in brown-black color. | Most fluorescent stains bind non-covalently to proteins either through the polypeptide backbone or through interaction with the SDS coat around the proteins |
| Typical protocol time | 10-135 min | 30-120 min | 60 min |
| Detection | Visual | Visual | UV or blue/green-light transilluminators or imaging instruments with appropriate filters |
| Compatibility with downstream applications | MS and sequencing compatible, western blotting (only non-fixative methods) | Certain formulations are MS compatible | Most stains are MS compatible, western blotting |
| Advantages | Quick and simple staining protocols, inexpensive | Lowest detection limits not requiring specialized equipment | Broad linear dynamic range with low detection limits |
| Learn more | Learn more | Learn more |
Coomassie dye stains
Coomassie dyes (also referred to as Coomassie blue or Coomassie brilliant blue) are common dyes used for the visualization of proteins separated by protein gel electrophoresis. Coomassie based stains offer easy staining protocols and provides good quantitative linearity with good sensitivity. Coomassie based dyes do not permanently chemically modify the target proteins rather interact via non-covalent interactions. Because no chemical modification occurs, excised protein bands can be completely de-stained and the recovered proteins can be used for analysis by mass spectrometry or sequencing.
In acidic conditions, Coomassie binds to basic and hydrophobic residues of proteins, changing in color from a dull reddish-brown to intense blue. As with all staining methods, Coomassie staining detects some proteins better than others, based on the chemistry of action and differences in protein composition. Thus, Coomassie staining can detect as little as 8–10 ng per band for some proteins and 25 ng per band for most proteins.
Two forms of the dye exists- R-250 (R standing for the reddish tint) and G-250 (G standing for the greenish tint). Both variants offer the same relative sensitivity and easy detection. Coomassie G-250 (also known as colloidal Coomassie dye) offers a faster staining protocols and eliminates the need for de-staining.
Silver dye stains
Silver staining is the most sensitive colorimetric method for detecting total protein. The technique involves the deposition of metallic silver onto the surface of a gel at the locations of protein bands. Silver ions (from silver nitrate in the staining reagent) interact and bind with certain protein functional groups. The strongest interactions occur with carboxylic acid groups (Asp and Glu), imidazole (His), sulfhydryls (Cys), and amines (Lys). Various sensitizer and enhancer reagents are essential for controlling the specificity and efficiency of silver ion binding to proteins and effective conversion (development) of the bound silver to metallic silver. The development process is essentially the same as for photographic film: silver ions are reduced to metallic silver, resulting in a brown-black color.
Silver staining protocols require several steps, which are affected by reagent quality as well as incubation times and thickness of the gel. An advantage of commercially available silver staining kits is that the formulations and protocols are optimized and consistently manufactured, helping to maximize consistency of results from experiment to experiment. Kits with optimized protocols are robust and easy to use, detecting less than 0.5 ng of protein in typical gels.
Silver stains use either glutaraldehyde or formaldehyde as the enhancer. These reagents can cause chemical crosslinking of the proteins in the gel matrix, limiting compatibility with de-staining and elution methods for analysis by mass spectrometry (MS). Therefore, optimization of sensitivity vs. protein recoverability is critical when employing silver staining as part of an MS workflow.
Silver stain formulations can be made such that protein bands stain black, blue-brown, red, or yellow, depending on their charge and other characteristics. This is particularly useful for differentiating overlapping spots on 2D gels.
Fluorescent dye stains
Fluorescent stains offer high sensitivity combined with simple staining protocols. Majority of fluorescent stains offer sensitivities similar to that obtained with silver staining techniques and can be used as a good alternative to silver staining in 1D or 2D electrophoresis. Unlike silver stains, fluorescent stains require equipment for visualization. Typical stains can be viewed with a standard UV or blue/green-light trans illuminator or with imaging equipment equipped with the appropriate filters. Fluorescent protein gel stains offer linear quantitation ranges, with some stains reporting over three orders of magnitude.
Nitrocellulose and PVDF membrane stains
| Pierce Reversible Protein Stain Kit | Ponceau S Staining Solution | SYPRO Ruby Blot Stain | No-Stain Protein Labeling Reagent | |
|---|---|---|---|---|
| Detection | Colorimetric (blue) | Colorimetric (pink-reddish) | Fluorescence (Ex: 280 & 450 nm, Em: 618 nm) | Fluorescence (Ex: 488 nm, Em: 590 nm) |
| Min. protein detected | ~25-50 ng | ~250 ng | ~2-8 ng | ~20 ng |
| Staining time | ~15 min | ~5 min | ~60 min | ~10 min |
| Applications | Monitoring transfer efficiency, total protein normalization after western blotting | |||
| Destaining before immunodetection | Destaining required | Destaining required | Not required | Not required |
| Considerations | Not recommended for fluorescent western blot detection | PVDF staining fixative required | ||
| Cat. No. | 24580 (nitrocellulose) 24585 (PVDF) | A40000279 (500 mL) | S11791 (200 mL) | A44449 (40 reactions) A44717 (10 reactions) |
Total protein stains
Colorimetric stains
| Product | Limit of detection | Components (steps)* | Time required** | Mass spec. compatible | Staining agent |
|---|---|---|---|---|---|
| GelCode Blue Safe Protein Stain | 9 ng | 2 (5) | 2 hr 15 min | Yes | G-250 |
| GelCode Blue Stain Reagent | 8 ng | 1 (5) | 2 hr 15 min | Yes | G-250 |
| Imperial Protein Stain | 3 ng | 1 (5) | 2 hr 15 min | Yes | R-250 |
| Simply Blue Safe Stain | >7 ng | 1 (5) | 12 min microwave 3 hr standard | Yes | G-250 |
| PageBlue Protein Stain | 5 ng | 1 (5) | 30 min microwave 90 min standard | Yes | G-250 |
| Colloidal Blue Staining | < 10 ng | 1 (3) | 10 hr | G-250 | |
| Pierce Silver Stain for Mass Spec | 0.25 ng | 6 (17) | 1 hr 13 min | Yes | Metallic silver ions |
| Pierce Silver Stain Kit | 0.25 ng | 4 (15) | 2 hr 25 min | Metallic silver ions | |
| Pierce Color Silver Stain Kit | 0.1 ng | 4 (9) | 4 hr 5 min | Yes | |
| Pierce Zinc Reversible Stain Kit | 0.25 ng | 3 (4) | 14 min | Yes | |
| SilverXpress Silver Staining Kit | 0.86 ng | 5 (13) | 2 hr | Metallic silver ions | |
| SilverQuest Silver Staining Kit | 0.3 ng | 7 (8) | 1 hr 30 min | Yes | Metallic silver ions |
| Pierce Reversible Protein Stain Kit for Nitrocellulose membranes | 25-50 ng | 3 (5) | 15 min | ||
| Pierce Reversible Protein Stain Kit for PVDF Membranes | 25-50 ng | 4 (8) | 15 min | ||
| Ponceau S Staining Solution | ~250 ng | 1 (3) | 15 min | Ponceau S |
Fluorescent stains
| Product | Limit of detection | Components (steps)* | Time required** | Mass spec. compatible | Excitation and emission maxima |
|---|---|---|---|---|---|
| SYPRO Ruby | 0.25- 1 ng | 1 (3) | 90 min microwave 18 hr standard | Yes | Excitation: 280, 450nm Emission: 610 nm |
| SYPRO Orange | 4-8 ng | 1 (5) | ~1 hr | Excitation: 300, 470nm Emission: 570 nm | |
| SYPRO Red | 4-8 ng | 1 (5) | ~1 hr | Excitation: 300, 550nm Emission: 630nm | |
| SYPRO Tangerine | 1-4 ng | 1 (4) | ~1 hr | Yes | Excitation: 300, 490nm Emission: 640nm |
| SYPRO Ruby blot stain | 2-8 ng | 1 (4) | ~1 hr | Yes | Excitation: 280, 450nm Emission: 618nm |
| Coomassie Fluor Orange | 8 ng | 1 (4) | ~1 hr | Excitation: 300, 470nm Emission: 570nm | |
| Krypton Fluorescent Protein Stain | 0.25 ng | 1 (7) | 2 hr 40 min | Yes | Excitation: 520nm Emission: 580nm |
*Some products require additional reagents to be supplied by user. The number of steps includes gel washes, solution changes, destaining steps, etc.
**Times include gel wash steps and all steps required for best sensitivity in a mini-gel. When less sensitivity is required, shorter staining and destaining times may be used with some protocols.
Functional group protein stains
| Product | Functional group | Limit of detection | Components (steps)* | Time required** | Detection method | Mass spec. compatible |
|---|---|---|---|---|---|---|
| Pro-Q Emerald 488 Glycoprotein Gel and Blot Stain Kit | Periodate-oxidized carbohydrate groups | 4 ng glycoprotein / band | 2 (13) | ~6 hrs | fluorescent | Yes |
| Pro-Q Emerald 300 Glycoprotein Gel and Blot Stain Kit | Periodate-oxidized carbohydrate groups | 0.5 ng glycoprotein / band | 2 (10) | ~5 hrs | UV | Yes |
| Pierce Glycoprotein Stain | Sialic acid and other oxidizable carbohydrate groups | 160 ng | 5 (11) | 2 hr 40 min | colorimetric | Not tested |
| Pro-Q Diamond Phosphoprotein Gel Stain | Phosphate groups attached to tyrosine, serine, or threonine residues | 1–16 ng phosphoprotein / band | 1 (5) | ~4-5 hrs | fluorescent | Not tested |
| Pro-Q Diamond Phosphoprotein Blot Stain Kit | Phosphate groups attached to tyrosine, serine, or threonine residues | 8-16 ng | 1 (6) | ~75 min | fluorescent | Yes |
| Lumio Green Detection Kit | Lumio, TC-tag | 1 pmole of a Lumio fusion protein | 3 (8) | Immediate | UV, fluorescent | Not tested |
| InVision™ His-tag In-gel Stain | 6X His-tag | ~0.5 picomole of a 6X His-tagged fusion protein | 2 (4) | <3 hrs | UV, fluorescent | Not tested |
| 6xHis Protein Tag Stain Kit | 6X His-tag | 200 ng | 4 (9) | 2 hr 20 min | UV, fluorescent | Not tested |
*Some products require additional reagents to be supplied by user. The number of steps includes multiple gel washes, solution changes, destaining steps, etc.
**Times include gel wash steps and all steps required for best sensitivity in a mini-gel. When less sensitivity is required, shorter staining and destaining times may be used with some protocols.
For Research Use Only. Not for use in diagnostic procedures.
