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Pro-Detect™ Rapid GST Assay Kit (Thermo Scientific™)

The Thermo Scientific Pro-Detect Rapid GST Assay Kit is a single-use, dipstick lateral flow kit for quick, easy detection of glutathione S transferase (GST)-tagged proteins in protein expression and purification systems. This lateral flow assay uses membrane-based strips coated with dye-bound conjugated antibodies specific to the GST tag to provide a visual, color readout for detection within ten minutes. This assay can be used to detect GST-tagged proteins directly from cell culture media (supernatant) or cell lysates without any special instrumentation or handling.

Features of the Pro-Detect Rapid assay kits:
Easy to adopt—lateral flow strips can be used early in and throughout expression to monitor and confirm expression of desired protein-tagged target
Simple, fast method—simply dilute sample using provided diluent and dip in the lateral flow strip for visual results within 5-10 minutes
Sensitive—detect protein tags in supernatant or cell lysate samples down to low µg/mL concentrations
Specific—assay does not cross-react with common lysis and protein preparation reagents
Reliable—results are similar to other antibody immunoassays, including western blot and ELISA
Long shelf life—stable for at least one year at 4°C

Each Pro-Detect Rapid assay is performed by simply adding a properly diluted tissue culture supernatant, lysate, or purified protein sample to a test tube or microplate well and dipping in a lateral flow strip. Gold-conjugated detection antibodies embedded in the strip form complexes with the tagged protein in the sample. These complexes travel the length of the strip membrane and bind at the test and control lines. Results are displayed as red bands.

Pierce™ Quantitative Peroxide Assay Kit (Lipid) (Thermo Scientific™)

The Thermo Scientific Pierce Quantitative Peroxide Assay Kit (lipid-compatible formulation) detects and measures hydrogen peroxide levels in biological samples using an iron and xylenol orange (XO) reagent.

This lipid-compatible peroxide assay kit detects peroxides based on oxidation of ferrous to ferric ion in the presence of xylenol orange. The kit's formulation may be used with lipid-containing samples without first extracting the lipids; however, because this kit does not contain sorbitol, the assay is less sensitive. Most proteins do not interfere with this assay, although some metal chelators may require use of a blank (i.e., control) to mitigate these effects.

Features of the Quantitative Peroxide Assay Kit:

Peroxides—detects and measures hydrogen peroxide (H2O2) levels in biological and other liquids samples
Convenient—no proprietary reagents involved but the ready-to-use kit removes the variability, difficulty and added expense of formulating the reagents yourself

Applications:
• General hydrogen peroxide (H2O2) measurement in protein samples
• Quantitation of peroxides in detergents
• Assessment of the effects of peroxides on cellular activity
• Determination of protein glycation; Measurement of peroxide accumulation in lipids

In this assay, hydroperoxides convert the Fe2+ to Fe3+ at acidic pH. With this lipid-compatible formulation, the peroxide converts the Fe2+ to Fe3+ directly. In a sulfuric acid solution, the Fe3+ complexes with the xylenol orange (XO) dye to yield a purple product having an absorbance maximum at 560nm. Peroxide levels in test samples can be determined by calculation from the known extinction coefficient of the XO-Fe complex or by reference to a standard curve prepared with hydrogen peroxide solution.

Related Products
Pierce™ Quantitative Peroxide Assay Kit (Aqueous)
Pierce™ Peroxide Assay Reagent A
Pierce™ Peroxide Assay Reagent B
Pierce™ Peroxide Assay Reagent C

Compat-Able™ Protein Assay Preparation Reagent Kit (Thermo Scientific™)

The Thermo Scientific Compat-Able Protein Assay Preparation Set eliminates interfering substances from protein assay samples to make them compatible with BCA and Bradford assays.

The Compat-Able Reagents remove salts, detergents, reducing agents and other substances from protein samples to eliminate interference with protein assays. The protocol selectively precipitates all of the protein, thereby allowing the non-protein components to be easily decanted and removed. The purified, precipitated protein is redissolved in water, making it ready for accurate determination of the protein concentration by standard protein assay methods. The procedure is accomplished in less than 10 minutes with just a few simple steps. The Compat-Able Preparation Set is available individually or conveniently bundled with either the Thermo Scientific Pierce BCA Protein Assay Kit or the Thermo Scientific Pierce Coomassie Plus Protein Assay Kit.

Features of the Compat-Able Protein Assay Preparation Reagent Kit:

Eliminate incompatibilities—removes nearly any substance that interferes with colorimetric protein assays: salts, detergents, denaturants, reducing agents, and even IEF sample buffer
Simple and fast—prepare samples in less than 10 minutes with four simple steps
Convenient—reagent set is easier to use than homemade TCA or acetone precipitation reagents, thereby producing more consistent results
Scalable—microcentrifuge method is easily scaled to larger centrifuge tube volumes for special needs
Validated—tested and offered together with BCA and Coomassie Plus Protein Assay Kits; protocol integrates control and normalization procedures

Related Products
Compat-Able™ BCA Protein Assay Kit
Compat-Able™ Coomassie Plus Protein Assay Kit

ProteinSEQ™ Protein A Core Kit (Applied Biosystems™)

The ProteinSEQ™ Protein A Core Kit is a partial kit that enables users to customize their ProteinSEQ protein measurements for leeched Protein A, or any other ligand used in their purification columns. It contains the buffers and reagents, but not the antibody-loaded capture beads, needed to enable PCR-based quantitation of Protein A or any other purification ligand. The kit contains sufficient reagents for 200 reactions. For a kit that includes Protein A capture beads and standards, for use in the quantitation of Protein A, please see the ProteinSEQ™ Protein A Quantitation Kit (Cat. No. 4469343).

• Quantitate leeched protein contaminants with ultra-high sensitivity
• Accelerate process development with more valid test results per run
• Reduce assay hands-on time with less sample dilution and preparation
• Achieve unprecedented productivity with near-5-log assay dynamic range

ProteinSEQ Protein A quantitation
The ProteinSEQ assay platform uses qPCR technology to measure process contaminants with extraordinary sensitivity and unparalleled dynamic range. Protein A or other purification ligands leeching from purification columns can be accurately measured with outstanding spike recovery and dilutional linearity.

Streamlined assay worflow
The ProteinSEQ system is the only instrument platform-based Protein A and purification ligand quantitation solution to offer single-digit picogram sensitivity and nearly 5 logs of dynamic range. Laboratory workflow is greatly accelerated due to the reduction in the number of sample dilutions and replicates in each run.

Pro-Detect™ Rapid V5 Competitive Assay Kit (Thermo Scientific™)

The Thermo Scientific Pro-Detect Rapid V5 Competitive Assay Kit is a single-use, dipstick lateral flow kit for quick, easy detection of V5-tagged proteins in protein expression and purification systems. This lateral flow assay uses membrane-based strips coated with dye-bound conjugated antibodies specific to V5 tag to provide a qualitative detection within ten minutes. This assay can be used to detect V5-tagged proteins directly from cell culture media (supernatant) or cell lysates without any special instrumentation or handling.

Features of the Pro-Detect Rapid competitive assay kits:
Easy to adopt—lateral flow strips can be used early in and throughout expression to monitor and confirm expression of desired protein-tagged target
Simple, fast method—simply dilute sample using provided diluent and dip in the lateral flow strip for qualitative results within 5-10 minutes
Sensitive—detect protein tags in supernatant or cell lysate samples down to low µg/mL concentrations
Specific—assay does not cross-react with common lysis and protein preparation reagents
Reliable—results are similar to other antibody immunoassays, including western blot and ELISA
Long shelf life—stable for at least one year at 4°C

Each Pro-Detect Rapid competitive assay is performed by simply adding a properly diluted tissue culture supernatant, lysate, or purified protein sample to a test tube or microplate well and dipping in a lateral flow strip. Gold-conjugated detection antibodies embedded in the strip form complexes with the tagged protein in the sample. In the presence of target protein tag, the dye-bound conjugated antibodies will bind to the tagged protein present in the sample instead of the protein tag bound at the test lines. Therefore, in a positive result, a competitive lateral flow assay will show decreasing intensity of the visible test lines until all test lines have disappeared. When there is no target protein tag present, the dye-bound conjugated antibodies specific to the target will bind at the test line(s), resulting in visual test lines in a negative result.

SphingoStrips™ Membranes (Invitrogen™)

SpingoStrips™ membranes are designed for the identification of proteins possessing phosphoinositide or sphingolipid recognition domains and for analysis of their lipid-binding specificities.

Pierce™ Peroxide Assay Reagent B (Thermo Scientific™)

Thermo Scientific Pierce Peroxide Assay Reagent B is a formulation consisting of 125µM xylenol orange in water with sorbitol. This formulation is one of the component of Quantitative Peroxide Assay Kit used for detecting and measuring hydrogen peroxide levels based on the oxidation of ferrous to ferric ion in the presence of xylenol orange, present in the biological and other liquid samples.

Features of Peroxide Assay Reagent B:

Convenient—no proprietary reagents involved and remove the variability, difficulty and added expense of formulating the reagents yourself
Aqueous-compatible formulations— the formulation includes sorbitol, which provides enhanced sensitivity with non-lipid samples

Applications of Pierce Quantitative Peroxide Assay Kits:
• General hydrogen peroxide (H2O2) measurement in protein samples
• Quantitation of peroxides in detergents
• Assessment of the effects of peroxides on cellular activity
• Determination of protein glycation; Measurement of peroxide accumulation in lipids

In these assay kits, hydroperoxides convert the Fe2+ to Fe3+ at acidic pH. With the aqueous-compatible formulation, peroxide first reacts with sorbitol, converting it to a peroxyl radical, which in turn initiates Fe2+ oxidation to Fe3+. In the lipid compatible formulation, the peroxide converts the Fe2+ to Fe3+ directly. In a sulfuric acid solution, the Fe3+ complexes with the xylenol orange (XO) dye to yield a purple product having an absorbance maximum at 560nm. Peroxide levels in test samples can be determined by calculation from the know extinction coefficient of the XO-Fe complex or by reference to a standard curve prepared with hydrogen peroxide solution.Most proteins do not interfere with these assays, although some metal chelators may require use of a blank (i.e., control) to mitigate these effects.

Related Products
Pierce™ Quantitative Peroxide Assay Kit (Aqueous)
Pierce™ Quantitative Peroxide Assay Kit (Lipid)
Pierce™ Peroxide Assay Reagent A
Pierce™ Peroxide Assay Reagent C

Pierce™ BCA Protein Assay Reagent A (Thermo Scientific™)

BCA Protein Assay Reagent A is a component of the Thermo Scientific Pierce BCA Protein Assay Kit, a two-component, high-precision, detergent-compatible assay reagent set to measure (A562nm) total protein concentration compared to a protein standard.

Used in more labs than any other detergent-compatible protein assay, Pierce BCA Reagents provide accurate determination of protein concentration with most sample types encountered in protein research. The Pierce BCA Assay can be used to assess yields in whole cell lysates and affinity-column fractions, as well as to monitor protein contamination in industrial applications. Compared to most dye-binding methods, the BCA Assay is affected much less by protein compositional differences, providing greater protein-to-protein uniformity.

Features of the Thermo Scientific Pierce BCA Protein Assay Kit (reagents A and B) :

Colorimetric—estimate visually or measure with a standard spectrophotometer or plate reader (562nm)
Excellent uniformity—exhibits less protein-to-protein variation than dye-binding methods
Compatible—unaffected by typical concentrations of most ionic and nonionic detergents
Moderately fast—much easier and four times faster than the classical Lowry method
High linearity—linear working range for BSA equals 20 to 2000 µg/mL
Sensitive—detect down to 5 µg/mL with the enhanced protocol

Applications:
• Studying protein:protein interactions
• Measuring column fractions after affinity chromatography
• Estimating percent recovery of membrane proteins from cell extracts
• High-throughput screening of fusion proteins

How the BCA Protein Assay Detects Protein:
The BCA Protein Assay combines the well-known reduction of Cu2+ to Cu1+ by protein in an alkaline medium with the highly sensitive and selective colorimetric detection of the cuprous cation (Cu1+) by bicinchoninic acid. The first step is the chelation of copper with protein in an alkaline environment to form a light blue complex. In this reaction, known as the biuret reaction, peptides containing three or more amino acid residues form a colored chelate complex with cupric ions in an alkaline environment containing sodium potassium tartrate.

In the second step of the color development reaction, bicinchoninic acid (BCA) reacts with the reduced (cuprous) cation that was formed in step one. The intense purple-colored reaction product results from the chelation of two molecules of BCA with one cuprous ion. The BCA/copper complex is water-soluble and exhibits a strong linear absorbance at 562 nm with increasing protein concentrations. The BCA reagent is approximately 100 times more sensitive (lower limit of detection) than the pale blue color of the first reaction.

The reaction that leads to BCA color formation is strongly influenced by four amino acid residues (cysteine or cystine, tyrosine, and tryptophan) in the amino acid sequence of the protein. However, unlike the Coomassie dye-binding methods, the universal peptide backbone also contributes to color formation, helping to minimize variability caused by protein compositional differences.

For more information, see the article "Chemistry of Protein Assays" in the Protein Methods Library.

Related Products
Pierce™ BCA Protein Assay Kit
Pierce™ BCA Protein Assay Reagent B
Pierce™ BCA Solid

Pro-Detect™ Rapid Antibody Isotyping Assay Kit, rat (Thermo Scientific™)

The Thermo Scientific Pro-Detect Rapid Antibody Isotyping Assay Kit - Rat is a single-use, dipstick lateral flow kit for quick, easy determination of rat monoclonal antibody class and subclass identity. This antibody isotyping assay uses membrane-based strips coated with dye-bound conjugated antibodies that provide a visual, color readout of the monoclonal antibody isotype within ten minutes. The kit determines rat IgG1, IgG2a, IgG2b , and IgG2c.

Features of the Pro-Detect Rapid Antibody Isotyping Assay Kit:
Long shelf life—stable for at least one year at 4°C
Simple workflow—dilute antibody sample using provided diluent and dip in the lateral flow strip
Fast—within 5–10 minutes a band appears that indicates the antibody isotype
Sensitive—detect antibodies in tissue culture media or ascites fluid samples down to low ng/mL concentrations
Specific—assay does not cross-react with fetal bovine serum (FBS)
Reliable—results are similar to standard ELISA-based isotyping assays

Each Pro-Detect Rapid Antibody Isotyping assay is performed by simply adding a properly diluted tissue culture supernatant or mouse ascites sample to a test tube or microplate well and dipping in a lateral flow strip. Gold conjugates embedded in the strip membrane form specific class- and subclass-soluble complexes with the antibodies in the sample. These complexes travel the length of the membrane and are resolved on the anti-isotype and class-specific antibody-impregnated regions of the membrane. Results are displayed as a red band above the printed class or sub-class description, indicating the antibody isotype present.

Determining the subclass of a rat antibody is important when selecting the best purification method. IgG2a, IgG2b, and IgG2c can be purified with Protein A columns at a pH of 7–8. IgG1 isotypes bind best to Protein A at a slightly higher pH of 8–9.

The Pro-Detect Rapid Antibody Isotyping Assay Kit is compatible with both tissue culture supernatant and mouse ascites fluid, and is more sensitive than conventional latex bead-based dipstick assays and much faster than ELISA-based isotyping assays. The kit requires only 0.5 µL ascites fluid, 2–22 µL of cell culture supernatant or 1.5 ng of purified antibody.

96-Well Plates for Pierce™ BCA-RAC Assay (Thermo Scientific™)

These are polystyrene 96-well round-bottom plates suitable for use with Thermo Scientific BCA-RAC (reducing agent compatible) assays.

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Pierce™ Microplate BCA Protein Assay Kit - Reducing Agent Compatible
Pierce™ BCA Protein Assay Kit - Reducing Agent Compatible

Quant-iT™ Protein Assay Kit (Invitrogen™)

The Quant-iT Protein Assay Kit makes protein quantitation easy and accurate. The kit provides concentrated assay reagent, dilution buffer, and pre-diluted BSA standards. Simply dilute the reagent, load it into the wells of a microplate, add 1-20 µL of sample, mix, then measure the fluorescence. The assay is highly selective for protein and exhibits very little protein-to-protein variation. The assay is performed at room temperature, and the signal is stable for 3 hours. Common contaminants, such as salts, solvents, or DNA—but not detergents—are well tolerated in the assay. Quant-iT DNA Assay Kits (Q33120, Q33130) and a Quant-iT RNA Assay Kit (Q33140) are also available.

Pro-Detect™ Rapid His Competitive Assay Kit (Thermo Scientific™)

The Thermo Scientific Pro-Detect Rapid His Competitive Assay Kit is a single-use, dipstick lateral flow kit for quick, easy detection of poly-histidine (His)-tagged proteins in protein expression and purification systems. This lateral flow assay uses membrane-based strips coated with dye-bound conjugated antibodies specific to His tag to provide a qualitative detection within ten minutes. This assay can be used to detect His-tagged proteins directly from cell culture media (supernatant) or cell lysates without any special instrumentation or handling.

Features of the Pro-Detect Rapid competitive assay kits:
Easy to adopt—lateral flow strips can be used early in and throughout expression to monitor and confirm expression of desired protein-tagged target
Simple, fast method—simply dilute sample using provided diluent and dip in the lateral flow strip for qualitative results within 5-10 minutes
Sensitive—detect protein tags in supernatant or cell lysate samples down to low µg/mL concentrations
Specific—assay does not cross-react with common lysis and protein preparation reagents
Reliable—results are similar to other antibody immunoassays, including western blot and ELISA
Long shelf life—stable for at least one year at 4°C

Each Pro-Detect Rapid competitive assay is performed by simply adding a properly diluted tissue culture supernatant, lysate, or purified protein sample to a test tube or microplate well and dipping in a lateral flow strip. Gold-conjugated detection antibodies embedded in the strip form complexes with the tagged protein in the sample. In the presence of target protein tag, the dye-bound conjugated antibodies will bind to the tagged protein present in the sample instead of the protein tag bound at the test lines. Therefore, in a positive result, a competitive lateral flow assay will show decreasing intensity of the visible test lines until all test lines have disappeared. When there is no target protein tag present, the dye-bound conjugated antibodies specific to the target will bind at the test line(s), resulting in visual test lines in a negative result.

Pierce™ Rapid Antibody Isotyping Kit - Mouse (Thermo Scientific™)

The Thermo Scientific Pierce Rapid Mouse Antibody Isotyping Kit is a single-use, cassette-based kit for 5-minute lateral-flow assay determination of mouse monoclonal antibody class and subclass identity.

This antibody isotyping kit uses cartridges that provide a color-readout of the monoclonal antibody isotype within five minutes after pipetting a small amount of diluted culture supernatant or ascites fluid sample into the sample well. The kit determines mouse IgG1, IgG2a, IgG2b, IgG3, IgA, IgM.

Features of the Pierce Rapid Mouse Antibody Isotyping Kit:

Long shelf life—stable for at least one year at room temperature
Single-step—add diluted antibody sample to the loading-well of cassette
Fast—within 5 minutes a band appears that indicates the antibody isotype
Sensitive—detect antibodies in tissue culture media or ascites fluid samples at any concentration greater than 10 ng/mL
Specific—assay does not cross-react with fetal bovine serum (FBS)
Reliable—results are similar to the standard ELISA-based isotyping assays

Each Pierce Rapid Isotyping Kit assay is performed by simply adding a properly diluted tissue culture supernatant or mouse ascites sample to the well of the small cassette. Gold conjugates embedded in the cassette form specific class- and subclass-soluble complexes with the antibodies in the sample. These complexes travel the length of the membrane and are resolved on the anti-isotype and class-specific antibody-impregnated membrane. Results are displayed as a red band indicating the antibody isotype or subclass.

Determining the class and subclass of a monoclonal antibody is useful in planning the best immunoglobulin purification method. For example, mouse IgA and IgM are best purified by size (i.e., gel exclusion) or using immunoaffinity separation columns. Mouse IgG2a and IgG2b are purified with immobilized Protein A at pH 7-8, while Mouse IgG1 binds best to Protein A at pH 8-9. Immunoglobulin that contains kappa light chains can be purified using immobilized Protein L.

The Pierce Rapid Isotyping Kit is compatible with both tissue culture supernatant and mouse ascites fluid, and is more sensitive than conventional latex-bead based dipstick assays and much faster than ELISA-based isotyping assays. The kit requires only 0.5µL ascites fluid, 5 to 55µL of cell culture supernatant or 1.5ng of purified antibody.

Related Products
Rapid ELISA Mouse mAb Isotyping Kit
Pierce™ Rapid Antibody Isotyping Kit plus Kappa and Lambda - Mouse

NanoOrange™ Protein Quantitation Kit, 200-2,000 assays (Invitrogen™)

The NanoOrange Protein Quantitation Kit contains a very sensitive and easy assay for protein quantitation, with detection as low as 10 ng/mL of protein in solution. This fluorescent dye is suitable for use with spectrofluorometers and microplate readers. For detection of lipoproteins or proteins in a complex lipid environment, check out our CBQCA Protein Quantitation Kit (C-6667).

Pierce™ Detergent Compatible Bradford Assay Reagent (Thermo Scientific™)

The Thermo Scientific™ Pierce™ Detergent Compatible Bradford Assay Reagent is a quick and ready-to-use modification of the well-known Bradford coomassie dye-binding, colorimetric method for total protein quantitation. Proprietary additives to the Bradford Reagent make it compatible with up to 1% or higher of detergents and lysis reagents that are commonly used in life science research, including Triton® X-100 and NP-40.

• Convenient—detergent-free standard curve
• Flexible—compatible with samples both with and without detergent
• Minimal sample—requires only 10 µL for microplate procedure
• Colorimetric—measure with a standard spectrophotometer or plate reader (595 nm)
• Easy to use—single reagent, no working reagent preparation required
• Fast—10 minute incubation at room temperature
• Broad range—detects protein concentration in the ranges of 2 to 1500 µg/mL

Similar to the Bradford method, coomassie dye binds protein in an acidic medium causing an immediate shift in absorption maximum from 465 nm to 595 nm with a concomitant color change from green to blue. In addition, the assay is complete in just 10 minutes.

The protein assay can be performed in either test tube or microplate format. The standard working range is 100-1500 µg/mL with up to 1% detergent (or higher in some cases). Protein concentrations are estimated by reference to absorbances obtained for a series of standard protein dilutions, typically bovine serum albumin (BSA), which are assayed alongside the unknown samples. Because the color response with coomassie dye is non-linear with increasing protein concentration, a standard curve must be completed with each assay. Standards can be used directly without preparing them in the same detergent found in the test samples.