Shop All Class-Specific Protein Assay Kits

BOVIGAM™ Tuberculin PPD Stimulating Antigen, bovine (30,000 I.U./mL) Thermo Scientific™

Bovine Tuberculin PPD is used for sensitive and specific BOVIGAM® stimulation. PPD is added to the blood sample to stimulate blood lymphocytes to produce IFN-γ.

BACE1 (β-Secretase) FRET Assay Kit, red

BACE1 (β-secretase) is a key enzyme involved in the production of Amyloid beta-peptides (Abeta) found in extracellular amyloid plaques of Alzheimers disease (AD). In some cases, early onset familial AD can be attributed to a "Swedish" mutation in the amyloid precursor protein (APP), dramatically enhancing the cleavage of this protein by BACE1. This and other genetic and pathological evidence has led to therapeutic approaches focusing on the inhibition of BACE1 and other APP-cleaving enzymes, such as gamma-secretase. The BACE1 fluorescence resonance energy transfer (FRET) Assay Kit provides a sensitive and efficient method for screening potential BACE1 inhibitors. This kit uses purified baculovirus-expressed BACE1 and a new red FRET peptide substrate based on the "Swedish" mutant.

The BACE1 FRET Assay Kit offers:

• Red emission to reduce compound interference
• Excitation at 545 nm and read emission at 585 nm
• An easy-to-use, rapid, homogeneous assay that is performed in solution
• Versatile formatting for high-throughput screening
• Stable results—measurements can be made for up to 24 hours

The principle of the BACE1 FRET assay is as follows: The peptide substrate is synthesized with two fluorophores, a fluorescent donor (a rhodamine (Rh) derivative), and a proprietary quenching acceptor. The distance between these two groups has been selected so that upon light excitation, the donor (D) fluorescence energy is significantly quenched by the acceptor (A) through a quantum mechanical phenomenon known as resonance energy transfer (Figure 1). Upon cleavage by the protease, the fluorophore is separated from the quenching group, restoring the full fluorescence yield of the donor. Thus, a weakly fluorescent peptide substrate becomes highly fluorescent upon enzymatic cleavage; the increase in fluorescence is linearly related to the rate of proteolysis.

Source of BACE1 Enzyme:
A cDNA sequence encoding amino acids 1-460 of human BACE1, corresponding to the ectodomain, was expressed in recombinant, baculovirus-infected insect cells. Purified BACE1 exists as the proBACE1 form having an apparent molecular weight of 55 kDa and an N-terminal sequence of TQHGIRLPLR.

BOVIGAM™ Tuberculin PPD Stimulating Antigen, avian (25,000 I.U./mL) Thermo Scientific™

Avian Tuberculin PPD is used as a stimulation control for the BOVIGAM® test. Avian PPD is added to the blood sample to control for unspecific stimulation of blood lymphocytes.

KDalert™ GAPDH Assay Kit with Manual Invitrogen™

The Ambion® KDalert™ GAPDH Assay Kit is for the reliable measure of GAPDH enzyme activity in cultured human, mouse, or rat cells in less than 30 minutes using a microplate fluorometer. The kit includes sufficient reagents for 375 reactions.

• Assess GAPDH siRNA delivery in 1/3 the time for 1/3 the cost of real-time PCR
• Analyze 1–96 samples simultaneously
• Measure both GAPDH siRNA-induced knockdown AND transfection-induced toxicity
• Compatible with a wide variety of cells and a broad range of culture conditions

The KDalert GAPDH Assay Kit is an ideal positive control for transfection optimization experiments and also measures transfection induced cytoxicity. It is designed for use with Ambion® Silencer® GAPDH siRNA.

Rapid, Time-Saving Procedure
Use the assay to optimize siRNA transfection by transfecting individual cell samples with a GAPDH siRNA and a negative control siRNA. Two to three days after transfection, simply add the included cell lysis buffer to the cells, incubate for 20 minutes, add the diluted master mix of assay reagents, and read the increase in fluorescence four minutes later using a microplate or standard fluorometer. The assay procedure can be completed in about 30 minutes with minimal sample handling.

One Assay for Two Readouts
Because GAPDH is expressed at relatively constant levels, the assay can also be used to monitor transfection agent induced toxicity. For this analysis, GAPDH enzyme activity from negative control siRNA-transfected cells is compared to that of untreated cells. Reduced GAPDH activity in negative control-transfected cells compared to non-transfected cells is an indication that the transfection-induced cytotoxicity.

Accessory Products:
The KDalert™ Kit is designed for use with Silencer® GAPDH siRNAs (SKUs #AM4605, AM4633, AM4634, AM4624, AM4632, or AM4631). Additional KDalert™ Lysis Buffer (SKU #AM8790G) is also available separately.

BOVIGAM™ PC-EC Stimulating Antigen (lyophilized) Thermo Scientific™

This is a tuberculin peptide cocktail based on the AHVLA ESAT-6 and CFP-10 antigens, for highest specificity in stimulation for BOVIGAM® products. It is ideal for bovine tuberculosis monitoring purposes.

BOVIGAM™ TB Kit, for USA Thermo Scientific™

The BOVIGAM® test is a blood-based in vitro laboratory test for bovine tuberculosis. It is based on the detection of cell-mediated immune response to infection with Mycobacterium bovis in cattle, sheep, goats, buffalo, bison, and other bovidae. The BOVIGAM® test involves two stages. In the first stage, blood samples are incubated overnight with antigens, such as tuberculin purified protein derivative (PPD) or the newly developed 'peptide cocktails', to stimulate lymphocytes to produce IFN-γ. In the second stage, IFN-γ in the plasma supernatants of each blood aliquot is determined using a sandwich ELISA. IFN-γ present in the sample binds to anti-bovine IFN-γ monoclonal antibodies on a solid support and is visualized with a second anti-IFN-γ antibody labeled with an enzyme that generates a color signal. Color development is proportional to the amount of bound IFN-γ.

LIVE/DEAD™ Fixable Aqua Dead Cell Stain Kit, for 405 nm excitation Invitrogen™

The LIVE/DEAD™ Fixable Aqua Dead Cell Stain Kit is used to determine the viability of cells prior to the fixation and permeabilization required for intracellular antibody staining or prior to elimination of biohazardous materials using formaldehyde fixation. This kit has been optimized and validated for use with a violet laser flow cytometer.

• Stable—dyes are freeze dried in separate vials to maintain stability

• Robust—staining pattern is the same before and after fixation

• Low compensation—minimal spectral overlap between other fluorophores

View a selection guide for all fixable viability dyes for flow cytometry.

Stable
Unlike products that are sold in solution, the LIVE/DEAD™ Fixable Aqua Stain has been conveniently packaged in 40-test vials to help ensure the stability and performance of the dye over time. Amine reactive dyes in solution will lose their effectiveness over a short period of time, therefore it is recommended to completely use the vial once rehydrated. If this is not possible, aliquot the vials in small volumes and store at -80°C, avoiding freeze-thaw cycles.

Robust
Dead cell discriminator stains can lose sensitivity after treatment with fixatives such as formaldehyde or ethanol-based fixation methods required for intracellular phosphorylation studies. The LIVE/DEAD™ Fixable Aqua Stain is an amine reactive dye that binds covalently to intracellular and extracellular amines, and the staining pattern is preserved following formaldehyde fixation.

Low compensation
The LIVE/DEAD™ Fixable Aqua Stain was selected based on its fluorescent properties to minimize compensation between other violet dyes and dyes that excite off of the 488 nm blue laser. The aqua-fluorescent reactive dye has an excitation maximum of ~375 nm, but it is excited well with the 405 nm violet laser, and it has an emission maxima of ~512 nm, so it can be collected in the second channel on most violet laser flow cytometers.

How it works
In cells with compromised membranes, the dye reacts with free amines both in the cell interior and on the cell surface, yielding intense fluorescent staining. In viable cells, the dye's reactivity is restricted to the cell-surface amines, resulting in less intense fluorescence. The difference in intensity is typically greater than 50-fold between live and dead cells, allowing for easy discrimination.

Colors available
LIVE/DEAD™ Fixable Dead Cell Stains are available in a wide variety of colors to meet your multi-color panel needs.

BOVIGAM™ 2G TB Kit Thermo Scientific™

The BOVIGAM® 2G kit is a blood-based assay of cell-mediated immunity that has been validated together with tuberculin PPDs and a panel of stimulation antigens. The combined use of these different stimulation antigens with tuberculin PPDs allows adjustment of the application of the test to specific TB situations. It is based on the detection of cell-mediated immune response to infection with Mycobacterium bovis in cattle, sheep, goats, buffalo, bison, and other bovidae. The BOVIGAM® 2G test involves two stages. In the first stage, blood samples are incubated overnight with antigens, such as tuberculin purified protein derivative (PPD) or the newly developed 'peptide cocktails', to stimulate lymphocytes to produce IFN-γ. In the second stage, IFN-γ in the plasma supernatants of each blood aliquot is determined using a sandwich ELISA. IFN-γ present in the sample binds to anti-bovine IFN-γ monoclonal antibodies on a solid support and is visualized with a second anti-IFN-γ antibody labeled with an enzyme that generates a color signal. Color development is proportional to the amount of bound IFN-γ.

BOVIGAM™ TB Kit Thermo Scientific™

The BOVIGAM® test is a blood-based in vitro laboratory test for bovine tuberculosis. It is based on the detection of cell-mediated immune response to infection with Mycobacterium bovis in cattle, sheep, goats, buffalo, bison, and other bovidae. The BOVIGAM® test involves two stages. In the first stage, blood samples are incubated overnight with antigens, such as tuberculin purified protein derivative (PPD) or the newly developed 'peptide cocktails', to stimulate lymphocytes to produce IFN-γ. In the second stage, IFN-γ in the plasma supernatants of each blood aliquot is determined using a sandwich ELISA. IFN-γ present in the sample binds to anti-bovine IFN-γ monoclonal antibodies on a solid support and is visualized with a second anti-IFN-γ antibody labeled with an enzyme that generates a color signal. Color development is proportional to the amount of bound IFN-γ.

BOVIGAM™ PC-HP Stimulating Antigen (lyophilized) Thermo Scientific™

This is a unique Mycobacterium tuberculosis-specific antigen cocktail with peptides derived from ESAT-6, CFP-10, and 4 additional mycobacterial genes. It is used for combined high sensitivity and specificity stimulation for BOVIGAM® products and represents the best compromise between high sensitivity and specificity that fulfills all requirements of eradication programs.

Glycoprotein Standards Set for Pierce™ Glycoprotein Carbohydrate Estimation Kit Thermo Scientific™

The Thermo Scientific Pierce Glycoprotein Standards Set includes six purified standards (two negative and four positive controls) intended for use with any glycoprotein carbohydrate determination protocol.

Related Products
Pierce™ Glycoprotein Carbohydrate Estimation Kit

KDalert™ GAPDH Assay Kit Invitrogen™

The Ambion® KDalert™ GAPDH Assay Kit is for the reliable measure of GAPDH enzyme activity in cultured human, mouse, or rat cells in less than 30 minutes using a microplate fluorometer. The kit includes sufficient reagents for 375 reactions.

• Assess GAPDH siRNA delivery in 1/3 the time for 1/3 the cost of real-time PCR
• Analyze 1-96 samples simultaneously
• Measure both GAPDH siRNA-induced knockdown AND transfection-induced toxicity
• Compatible with a wide variety of cells and a broad range of culture conditions

The KDalert GAPDH Assay Kit is an ideal positive control for transfection optimization experiments and also measures transfection induced cytoxicity. It is designed for use with Ambion® Silencer® GAPDH siRNA.

Rapid, Time-Saving Procedure
Use the assay to optimize siRNA transfection by transfecting individual cell samples with a GAPDH siRNA and a negative control siRNA. Two to three days after transfection, simply add the included cell lysis buffer to the cells, incubate for 20 minutes, add the diluted master mix of assay reagents, and read the increase in fluorescence four minutes later using a microplate or standard fluorometer. The assay procedure can be completed in about 30 minutes with minimal sample handling.

One Assay for Two Readouts
Because GAPDH is expressed at relatively constant levels, the assay can also be used to monitor transfection agent induced toxicity. For this analysis, GAPDH enzyme activity from negative control siRNA-transfected cells is compared to that of untreated cells. Reduced GAPDH activity in negative control-transfected cells compared to non-transfected cells is an indication that the transfection-induced cytotoxicity.

Accessory Products:
The KDalert™ Kit is designed for use with Silencer® GAPDH siRNAs (SKUs #AM4605, AM4633, AM4634, AM4624, AM4632, or AM4631). Additional KDalert™ Lysis Buffer (SKU #AM8790G) is also available separately.

Pierce™ Phosphoprotein Phosphate Estimation Assay Kit Thermo Scientific™

The Thermo Scientific Phosphoprotein Phosphate Estimation Kit enables classification and identification of proteins as phosphorylated (serine and threonine), as well as semi-quantitative assessment of the phosphorylation level.

Features of the Phosphoprotein Phosphate Estimation Kit:

Specific—measures phosphoserine (p-Ser) and phosphothreonine (p-Thr) only; does not measure phosphotyrosine (p-Tyr)
Convenient—test tube and 96-well microplate protocols included and require less than 90 minutes to perform
Semi-quantitative—calculate moles of phosphate (P) per mole of protein using the included phosvitin standard
Customizable—format is adaptable to development of specific assays for pure phosphoproteins when previously characterized standards are available

The Phosphoprotein Phosphate Estimation Assay Kit is designed to aid in characterization of the status and extent of phosphorylation of purified protein samples. The assay is based on the alkaline hydrolysis of phosphate from seryl and threonyl residues in phosphoproteins and quantification of the released phosphate with malachite green and ammonium molybdate. The assay is easily performed in 96-well microplates or test tubes and is completed in about one hour.

Applications:
• Identify proteins as containing phosphoserine or phosphothreonine phosphorylations
• Estimate the amount of pS and pT phosphorylation
• Develop specific quantitative assays for well-characterized phosphoproteins of interest

The assay can be used to identify whether a purified protein contains either phospho-serine (p-Ser) or phospho-threonine (p-Thr) as well as to estimate the level of this type of phosphorylation. For quantitation, the test protein sample is compared with specific concentrations of phosvitin, a phosphoprotein of known phosphorylation level. The alkaline hydrolysis step does not release phosphate from phospho-tyrosine (p-Tyr) residues in peptide linkage. Therefore, a negative result for an unknown purified protein preparation indicates that the protein is either (1) not a phosphoprotein or (2) is phosphorylated exclusively at tyrosine residues. In the latter case, Western blot analysis using an anti-phosphotyrosine antibody will be necessary to distinguish between these two possibilities.

LanthaScreen™ TR-FRET BACE1 Assay Kit Thermo Scientific™

BACE1 (beta-secretase) is a key enzyme involved in the production of amyloid beta-peptides found in extracellular amyloid plaques of Alzheimer’s disease (AD). In some cases, early-onset familial AD can be attributed to a "Swedish"mutation in the amyloid precursor protein (APP), which dramatically enhances the cleavage of this protein by BACE1. This and other genetic and pathological evidence has led to therapeutic approaches that focus on the inhibition of BACE1 and other APP-cleaving enzymes, such as gamma-secretase.

Invitrogen’s LanthaScreen® TR-FRET BACE1 assay provides sensitive high-throughput screening for potential inhibitors of beta-secretase. The kit uses a terbium (Tb)-labeled anti-biotin antibody and a fluorescein-labeled BACE1-biotin substrate in a homogeneous TR-FRET assay format (Figure 1).



Contents and Storage:

The LanthaScreen® TR-FRET BACE1 Assay Kit contains BACE1 protein, fluorescently labeled BACE1 substrate, Tb-labeled anti-biotin antibody, and buffers. Store components as indicated in the assay protocol (-80°C, -20°C, or +4°C).

Pierce™ Colorimetric Protease Assay Kit Thermo Scientific™

The Thermo Scientific Pierce Colorimetric Protease Assay Kit measures total protease activity in samples, providing a means to assess the progress of protease isolation procedures or quantify protease contamination in biological samples. This kit uses fully succinylated casein as a substrate for the assay. Hydrolysis of this substrate in the presence of protease results in the release of peptide fragments with free amino-terminal groups. These peptides are reacted with trinitrobenzene sulfonic acid (TNBSA), followed by measurement of the absorbance increase that results from the formation of yellow colored TNB-peptide adducts.

Features of the Colorimetric Protease Assay Kit:

Casein substrate—measure activity of any protease that cleaves casein into peptide fragments
Trypsin standard—quantify protease activity relative to trypsin, a universally accepted reference
Sensitive—1000 times more sensitive than assays that use unmodified forms of casein
Simple and fast—test tube and microplate protocols are completed in less than one hour
Homogenous—addition steps only; no separation, transfer or stop steps required
Customizable—easily adapt time, temperature and pH to optimize sensitivity for proteases of interest

Applications:
• Assess functional integrity and overall progress of protease purification
• Quantify protease contamination in protein samples
• Characterize the activity of unusual proteases compared to trypsin
• Evaluate buffer conditions for their affects on protease function and activity

Additional Specifications:
• Substrate: succinylated casein (not available separately)
• Basis of assay: detection of primary amines resulting from proteolysis
• Detection reagent: trinitrobenzene sulfonic acid (TNBSA)
• Measurement: absorbance at 450nm (plate reader or spectrophotometer)

Related Products
Pierce™ Fluorescent Protease Assay Kit
FITC-Casein for Pierce™ Fluorescent Protease Assay Kit
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