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Amplex™ Red Cholesterol Assay Kit (Invitrogen™)

The Amplex® Red Cholesterol Assay Kit provides a sensitive, rapid, and simple fluorometric method for detecting very low concentrations of cholesterol using a fluorescence microplate reader or fluorometer. The assay measures both free cholesterol and cholesteryl esters.

See our complete line of Fluorescence Microplate assays.

 Detects as little as 200 nM (80 ng/ml) cholesterol
•  Helps accurately measure cholesterol content of 0.01 µl of human serum
•  Detects both free cholesterol and cholesteryl esters
•  Allows for multiple time point measurements
•  Designed for minimal autofluorescence interference

The Amplex Red Cholesterol Assay kit contains these reagents and buffers:


•  Amplex Red reagent
•  DMSO
•  Horseradish peroxidase
•  Hydrogen peroxide
•  Cholesterol esterase
•  Cholesterol oxidase
•  Cholesterol reference standard
•  Resorufin fluorescence reference standard
•  5X Reaction buffer

Cholesterol Measurement is Simple and Fast
Performing the Amplex® Red cholesterol assay is quick and easy, requiring only a 30-minute incubation after addition of reagents with no separation steps required. The 100 µl assay volume is designed for 96-well plates; fluorescence can be measured with a microplate reader or fluorometer. Since the assay is continuous, once the Amplex® Red reagent is added, multiple time-point measurements can be taken. The kit is complete with all necessary reagents except deionized water.

Helps Accurately Detect Very Low Cholesterol Concentrations
The Amplex® Red cholesterol assay utilizes enzyme-coupled reactions to produce highly fluorescent resorufin for quantitation. Resorufin is produced by the reaction of the Amplex® Red reagent with H2O2 produced from the cholesterol oxidase-catalyzed oxidation of cholesterol. Because a large proportion of cholesterol in blood is in the form of cholesteryl esters, cholesterol esterase is used to produce free cholesterol from cholesterol esters. Performing the assay in the presence and absence of cholesterol esterase potentially allows determination of the fractions of cholesterol in each form.

This highly sensitive method allows the Amplex® Red Cholesterol Assay kit to detect concentrations of cholesterol as low as 200 nM and measure the cholesterol content of 0.01 µl of human serum. Because the absorbance and emission maxima of resorufin are 571 nm and 585 nm respectively, autofluorescence in most biological samples does not interfere with the assay.

Use Amplex® Red Assays for a Broad Range of Investigations
A wide variety of validated Invitrogen Amplex® Red assays are available for studying cell signaling and lipids, neurobiology, inflammation and immune function, and metabolism. We also offer Amplex® UltraRed (Cat. No. A36006), a second-generation reagent providing greater sensitivity and brighter fluorescence and the Amplex® Red/UltraRed stop reagent (Cat. No. A33855). The Amplex® Red/UltraRed stop reagent provides convenience and control by allowing the fluorescence signal-generating reaction to be terminated at a user-determined time point. After addition of the stop reagent, the fluorescence signal remains stable for at least 3 hours. Custom assay design and packaging are also available.

For Research Use Only. Not intended for any animal or human therapeutic or diagnostic use.

Related Link
Learn More about Amplex® Red Assays and Technology.

Amplex™ Red Phosphatidylcholine-Specific Phospholipase C Assay Kit (Invitrogen™)

The Amplex® Red Phosphatidylcholine-Specific Phospholipase C Assay Kit provides a sensitive method for detecting phosphatidylcholine-specific phospholipase C (PC-PLC) activity using a fluorescence microplate reader or fluorometer.

See our complete line of Fluorescence Microplate assays.

• Detects phospholipase-C activity levels as low as 0.2 mU/mL
• Format allows for multiple time point measurements
• Designed for minimal autofluorescence interference

In this enzyme-coupled assay, PC-PLC activity is monitored indirectly using 10-acetyl-3,7-dihydroxyphenoxazine (Amplex® Red reagent), a sensitive fluorogenic probe for hydrogen peroxide. PC-PLC converts phosphatidylcholine (lecithin) to phosphocholine and diacylglycerol. Alkaline phosphatase is added, which hydrolyzes phosphorylcholine to form choline. Choline is then oxidized by choline oxidase to form betaine and hydrogen peroxide. In the presence of horseradish peroxidase, the hydrogen peroxide reacts with Amplex® Red reagent in a 1:1 stoichiometric ratio to generate the highly fluorescent product resorufin.

Because resorufin has absorption and fluorescence emission maxima of approximately 571 nm and 585 nm, respectively, there is little interference from autofluorescence in most biological samples.

Use Amplex® Red Assays for a Broad Range of Investigations
A wide variety of validated Amplex® Red assays are available for studying cell signaling and lipids, neurobiology, inflammation and immune function, and metabolism. We also offer Amplex® UltraRed Reagent (Cat. No. A36006), a second-generation reagent providing greater sensitivity and brighter fluorescence, and the Amplex® Red/UltraRed Stop Reagent (Cat. No. A33855). The Amplex® Red/UltraRed Stop Reagent provides convenience and control by allowing the fluorescence signal-generating reaction to be terminated at a user-determined time point. After addition of the stop reagent, the fluorescence signal remains stable for at least three hours. Custom assay design and packaging are also available.

Amplex™ Red Neuraminidase (Sialidase) Assay Kit (Invitrogen™)

The Amplex® Red Neuraminidase (Sialidase) Assay Kit provides a sensitive and simple method for detecting neuraminidase activity in serum and in purified enzyme systems using either a fluorescence microplate reader or fluorometer.

See our complete line of Fluorescence Microplate assays.

• Detect neuraminidase levels as low as 0.2 mU/mL
• Format allows for multiple time point measurements
• Designed for minimal autofluorescence interference
• Detect neuraminidase activity in biological samples such as serum

Neuraminidase (also known as sialidase) is a very common enzyme that hydrolyzes terminal sialic acid residues on polysaccharide chains, most often exposing a galactose residue. Neuraminidase plays a key role in the invasion of target cells and the subsequent replication of the influenza virus, making neuraminidase an important target for influenza drug development.

The Amplex® Red Neuraminidase (Sialidase) Assay Kit provides an ultrasensitive method for detecting neuramimidase activity. This assay utilizes Amplex® Red reagent to detect hydrogen peroxide generated by galactose oxidase oxidation of desialiated galactose, the end result of neuraminidase action. Then the hydrogen peroxide, in the presence of horseradish peroxidase (HRP), reacts in a 1:1 stoichiometric ratio with Amplex® Red reagent to generate the red-fluorescent oxidation product resorufin.

Because resorufin has absorption and fluorescence emission maxima of approximately 571 nm and 585 nm, respectively, there is little interference from autofluorescence in most biological samples.

Use Amplex® Red Assays for a Broad Range of Investigations
A wide variety of validated Amplex® Red assays are available for studying cell signaling and lipids, neurobiology, inflammation and immune function, and metabolism. We also offer Amplex® UltraRed Reagent (Cat. No. A36006), a second-generation reagent providing greater sensitivity and brighter fluorescence, and the Amplex® Red/UltraRed Stop Reagent (Cat. No. A33855). The Amplex® Red/UltraRed Stop Reagent provides convenience and control by allowing the fluorescence signal-generating reaction to be terminated at a user-determined time point. After addition of the stop reagent, the fluorescence signal remains stable for at least three hours. Custom assay design and packaging are also available.

Amplex™ Red Galactose/Galactose Oxidase Assay Kit (Invitrogen™)

The Amplex® Red Galactose/Galactose Oxidase Assay Kit provides a sensitive and simple method for detecting galactose oxidase activity or galactose using a fluorescence microplate reader or fluorometer.

See our complete line of Fluorescence Microplate assays.

• Detect concentrations as low as 2 mU/mL of galactose oxidase activity or 4 µM galactose
• Format allows for multiple time point measurements
• Designed for minimal autofluorescence interference

Galactose oxidase is an important tool in the detection of galactose in biological fluids. The Amplex® Red Galactose/Galactose Oxidase Assay Kit provides an ultrasensitive method for detecting galactose or for monitoring galactose oxidase activity. Galactose oxidase catalyzes the oxidation of galactose at the C6 position and generates hydrogen peroxide. In the presence of horseradish peroxidase (HRP), hydrogen peroxide reacts in a 1:1 stoichiometric ratio with the Amplex® Red reagent to generate the red-fluorescent compound resorufin.

Because resorufin has absorption and fluorescence emission maxima of approximately 571 nm and 585 nm, respectively, there is little interference from autofluorescence in most biological samples.

Use Amplex® Red Assays for a Broad Range of Investigations
A wide variety of validated Amplex® Red assays are available for studying cell signaling and lipids, neurobiology, inflammation and immune function, and metabolism. We also offer Amplex® UltraRed Reagent (Cat. No. A36006), a second-generation reagent providing greater sensitivity and brighter fluorescence, and the Amplex® Red/UltraRed Stop Reagent (Cat. No. A33855). The Amplex® Red/UltraRed Stop Reagent provides convenience and control by allowing the fluorescence signal-generating reaction to be terminated at a user-determined time point. After addition of the stop reagent, the fluorescence signal remains stable for at least three hours. Custom assay design and packaging are also available.

Amplex™ Red Sphingomyelinase Assay Kit (Invitrogen™)

The Amplex® Red Sphingomyelinase Assay Kit provides a sensitive, rapid, and simple fluorometric method for detecting very low concentrations of sphingomyelinase using a fluorescence microplate reader or fluorometer.

See our complete line of Fluorescence Microplate assays.

• Detects sphingomyelinase activity levels as low as 80 µU/mL in a 200 µL assay volume
• Format allows for multiple time point measurements
• Designed for minimal autofluorescence interference

In this enzyme-coupled assay, sphingomyelinase activity is monitored indirectly using 10-acetyl-3,7-dihydroxyphenoxazine (Amplex® Red reagent), a sensitive fluorogenic probe for hydrogen peroxide. Sphingomyelinase hydrolyses the sphingomyelin to yield ceramide and phosphorylcholine. Alkaline phosphatase is added, which hydrolyzes phosphorylcholine to form choline. The choline is then oxidized by choline oxidase to form betaine and hydrogen peroxide. In the presence of horseradish peroxidase, the hydrogen peroxide reacts with Amplex® Red reagent in a 1:1 stoichiometric ratio to generate the highly fluorescent product resorufin.

Because resorufin has absorption and fluorescence emission maxima of approximately 571 nm and 585 nm, respectively, there is little interference from autofluorescence in most biological samples.

Use Amplex® Red Assays for a Broad Range of Investigations
A wide variety of validated Amplex® Red assays are available for studying cell signaling and lipids, neurobiology, inflammation and immune function, and metabolism. We also offer Amplex® UltraRed Reagent (Cat. No. A36006), a second-generation reagent providing greater sensitivity and brighter fluorescence, and the Amplex® Red/UltraRed Stop Reagent (Cat. No. A33855). The Amplex® Red/UltraRed Stop Reagent provides convenience and control by allowing the fluorescence signal-generating reaction to be terminated at a user-determined time point. After addition of the stop reagent, the fluorescence signal remains stable for at least three hours. Custom assay design and packaging are also available.

ThiolTracker™ Violet (glutathione detection reagent) (Invitrogen™)

ThiolTracker™ Violet is a brighter and more robust intracellular thiol probe for reproducible GSH detection. Since reduced glutathione represents the majority of intracellular free thiols in the cell, ThiolTracker™ Violet can be used in estimating the cellular level of reduced glutathione.
ThiolTracker™ Violet offers the following;
• 10X brighter than mBCL
• UV or 405 nm excitation, 525 nm emission
• Easy to use
• Reproducible results
• Can be fixed with aldehydes and permeabilized by Triton® X-100 (0.5%)
• Formaldehyde fixable and suvives detergent extraction
• Can be used in multiplex assays including cytotoxicity studies
Subcellular detection and localization of GSH is important in understanding the modulation of redox status, the effect of drugs, and the mechanisms of detoxification. Furthermore, differences in GSH levels in response to oxidative stress in subpopulations of cells have been reported, underscoring the importance of detection methods amenable to flow cytometry and automated fluorescence detection. ThiolTracker™ Violet can be used for Flow Cytometry, HCS imaging, and epifluorescent microscopy.

Vybrant™ Cell Metabolic Assay Kit, with C12-resazurin (Invitrogen™)

In the Vybrant® Cell Metabolic Assay Kit, nonfluorescent C12-resazurin is reduced to fluorescent C12-resorufin by viable cells; the resulting signal is proportional to the number of cells present. C12-resazurin has better cellular retention than alamarBlue® dye and can be multiplexed with viability indicators and other biomarkers

Amplex™ Red Glutamic Acid/Glutamate Oxidase Assay Kit (Invitrogen™)

The Amplex® Red Glutamic Acid/Glutamate Oxidase Assay Kit provides a sensitive and simple method for detecting glutamic acid/glutamate oxidase activity using a fluorescence microplate reader or fluorometer.

See our complete line of Fluorescence Microplate assays.

• Detect concentrations as low as 10 nM L-glutamic acid or 40 µU/mL of purified L-glutamate oxidase
• Format allows for multiple time point measurements
• Designed for minimal autofluorescence interference

The Amplex® Red Glutamic Acid/Glutamate Oxidase Assay Kit provides an ultrasensitive method for detecting glutamic acid or for continuously monitoring glutamate oxidase activity using a fluorescence microplate reader or fluorometer. In the assay, L-glutamic acid is oxidized by glutamate oxidase to produce α-ketoglutarate, NH3, and hydrogen peroxide. L-alanine and L-glutamate–pyruvate transaminase are included in the reaction to regenerate L-glutamic acid by transamination of α-ketoglutarate, resulting in multiple cycles of the initial reaction and a significant amplification of the hydrogen peroxide produced. The hydrogen peroxide reacts with 10-acetyl-3,7-dihydroxyphenoxazine (Amplex® Red reagent) in a 1:1 stoichiometric ratio in a reaction catalyzed by horseradish peroxidase (HRP) to generate the highly fluorescent product resorufin.

Because resorufin has absorption and fluorescence emission maxima of approximately 571 nm and 585 nm, respectively, there is little interference from autofluorescence in most biological samples.

Use Amplex® Red Assays for a Broad Range of Investigations
A wide variety of validated Amplex® Red assays are available for studying cell signaling and lipids, neurobiology, inflammation and immune function, and metabolism. We also offer Amplex® UltraRed Reagent (Cat. No. A36006), a second-generation reagent providing greater sensitivity and brighter fluorescence, and the Amplex® Red/UltraRed Stop Reagent (Cat. No. A33855). The Amplex® Red/UltraRed Stop Reagent provides convenience and control by allowing the fluorescence signal-generating reaction to be terminated at a user-determined time point. After addition of the stop reagent, the fluorescence signal remains stable for at least three hours. Custom assay design and packaging are also available.

Amplex™ Red Hydrogen Peroxide/Peroxidase Assay Kit (Invitrogen™)

The Amplex® Red Hydrogen Peroxide/Peroxidase Assay Kit contains a sensitive, one-step assay that uses the Amplex® Red reagent (10-acetyl-3,7-dihydroxyphenoxazine) to detect hydrogen peroxide (H2O2) or peroxidase activity. The Amplex® Red reagent, in combination with horseradish peroxidase (HRP), has been used to detect H2O2 released from biological samples, including cells, or generated in enzyme-coupled reactions. Furthermore, Amplex® Red reagent can be used as an ultrasensitive assay for peroxidase activity when H2O2 is in excess. In the presence of peroxidase, the Amplex® Red reagent reacts with H2O2 in a 1:1 stoichiometry to produce the red-fluorescent oxidation product, resorufin. Resorufin has excitation and emission maxima of approximately 571 nm and 585 nm, respectively, and because the extinction coefficient is high (58,000 ± 5,000 cm–1M–1), you can perform the assay fluorometrically or spectrophotometrically. This reaction has been used to detect as little as 10 picomoles of H2O2 in a 100 µL volume or 1 x 10–5 U/mL of HRP.

Amplex® Red Hydrogen Peroxide/Peroxidase Assay Kit Specifications:
• Ex/Em of reaction product resorufin: ~571/585 nm
• Sensitive one-step assay to detect hydrogen peroxide or peroxidase in vitro
• Can detect as little as 10 picomoles of hydrogen peroxide or 10 µU/mL of horseradish peroxidase activity in a 100 µL assay volume
• Provides sufficient reagents for approximately 500 assays using reaction volumes of 100 µL per assay
• Designed for a 96-well fluorescence or absorbance microplate reader, but can be easily adapted for other volumes, for fluorimeters, and for spectrophotometers


Find More Substrates for Oxidases
Review Substrates for Oxidases, Including Amplex Red Kits—Section 10.5 in the Molecular Probes® Handbook for more information on these products.

For Research Use Only. Not for human or animal therapeutic or diagnostic use.

2-NBDG (2-(N-(7-Nitrobenz-2-oxa-1,3-diazol-4-yl)Amino)-2-Deoxyglucose) (Invitrogen™)

2-NBDG is a fluorescent glucose analog that has been used to monitor glucose uptake in live cells, as an indicator of cell viability. Although sensitive to its environment NBD fluorescence typically displays excitation/emission maxima of ~465/540 nm and can be visualized using optical filters designed for fluorescein.

ThiolTracker™ Violet (glutathione detection reagent) (Invitrogen™)

ThiolTracker™ Violet is a brighter and more robust intracellular thiol probe for reproducible GSH detection. Since reduced glutathione represents the majority of intracellular free thiols in the cell, ThiolTracker™ Violet can be used in estimating the cellular level of reduced glutathione.
ThiolTracker™ Violet offers the following;
• 10X brighter than mBCL
• UV or 405 nm excitation, 525 nm emission
• Easy to use
• Reproducible results
• Can be fixed with aldehydes and permeabilized by Triton® X-100 (0.5%)
• Formaldehyde fixable and suvives detergent extraction
• Can be used in multiplex assays including cytotoxicity studies
Subcellular detection and localization of GSH is important in understanding the modulation of redox status, the effect of drugs, and the mechanisms of detoxification. Furthermore, differences in GSH levels in response to oxidative stress in subpopulations of cells have been reported, underscoring the importance of detection methods amenable to flow cytometry and automated fluorescence detection. ThiolTracker™ Violet can be used for Flow Cytometry, HCS imaging, and epifluorescent microscopy.

Amplex™ Red Uric Acid/Uricase Assay Kit (Invitrogen™)

The Amplex® Red Uric Acid/Uricase Assay Kit provides a sensitive and simple method for detecting uric acid or uricase using either a fluorescence microplate reader or fluorometer.

See our complete line of Fluorescence Microplate assays.

• Detect concentrations as low as 100 nM uric acid or 0.2 mU/mL of uricase activity
• Format allows for multiple time point measurements
• Designed for minimal autofluorescence interference

Serum uric acid is the end product of purine metabolism in the body tissues and is cleared through the kidneys by glomerular filtration. Most animals can metabolize uric acid to more readily excreted products, but humans lack the necessary enzyme, urate oxidase (uricase), as a result of the presence of two “nonsense mutations” in the human gene for uricase.

The Amplex® Red Uric Acid/Uricase Assay Kit provides an ultrasensitive method for detecting uric acid or for monitoring uricase activity. In the assay, uricase catalyzes the conversion of uric acid to allantoin, hydrogen peroxide, and carbon dioxide. In the presence of horseradish peroxidase (HRP), hydrogen peroxide reacts stoichiometrically with the Amplex® Red reagent to generate the red-fluorescent oxidation product resorufin.

Because resorufin has absorption and fluorescence emission maxima of approximately 571 nm and 585 nm, respectively, there is little interference from autofluorescence in most biological samples.

Use Amplex® Red Assays for a Broad Range of Investigations
A wide variety of validated Amplex® Red assays are available for studying cell signaling and lipids, neurobiology, inflammation and immune function, and metabolism. We also offer Amplex® UltraRed Reagent (Cat. No. A36006), a second-generation reagent providing greater sensitivity and brighter fluorescence, and the Amplex® Red/UltraRed Stop Reagent (Cat. No. A33855). The Amplex® Red/UltraRed Stop Reagent provides convenience and control by allowing the fluorescence signal-generating reaction to be terminated at a user-determined time point. After addition of the stop reagent, the fluorescence signal remains stable for at least three hours. Custom assay design and packaging are also available.

Amplex™ Red Monoamine Oxidase Assay Kit (Invitrogen™)

The Amplex Red Monoamine Oxidase Assay Kit provides a sensitive and simple fluorometric method for detecting monoamine oxidase activity in purified enzyme preparations at levels as low as 12 µU/mL and in tissue samples with as little as 20 µg protein in a 100 µL assay volume.

Amplex™ Red Glucose/Glucose Oxidase Assay Kit (Invitrogen™)

The Amplex® Red Glucose/Glucose Oxidase Assay Kit provides a sensitive and simple method for detecting d-glucose or glucose oxidase using a fluorescence microplate reader or fluorometer.

See our complete line of Fluorescence Microplate assays.

• Detect concentrations as low as 3 µM d-glucose or 0.05 mU/mL of glucose oxidase
• Format allows for multiple time point measurements
• Designed for minimal autofluorescence interference

The Amplex® Red reagent (10-acetyl-3,7-dihydroxyphenoxazine) is a colorless, stable, and extremely versatile peroxidase substrate. Because peroxidase- and glucose oxidase-mediated reactions can be coupled, it is possible to measure glucose oxidase activity or the release of glucose by any glucosidase enzyme—for instance, β-glucosidase and glucocerebrosidase—in either a continuous or discontinuous assay. Because of the ability to couple reactions, this assay has been demonstrated to be useful for the quantification of glucose levels in foods, fermentation media, and bodily fluids.

In the assay, glucose oxidase reacts with d-glucose to form d-gluconolactone and hydrogen peroxide. In the presence of horseradish peroxidase (HRP), hydrogen peroxide then reacts with the Amplex® Red reagent in a 1:1 stoichiometric ratio to generate the red-fluorescent product resorufin.

Because resorufin has absorption and fluorescence emission maxima of approximately 571 nm and 585 nm, respectively, there is little interference from autofluorescence in most biological samples.

Use Amplex® Red Assays for a Broad Range of Investigations
A wide variety of validated Amplex® Red assays are available for studying cell signaling and lipids, neurobiology, inflammation and immune function, and metabolism. We also offer Amplex® UltraRed Reagent (Cat. No. A36006), a second-generation reagent providing greater sensitivity and brighter fluorescence, and the Amplex® Red/UltraRed Stop Reagent (Cat. No. A33855). The Amplex® Red/UltraRed Stop Reagent provides convenience and control by allowing the fluorescence signal-generating reaction to be terminated at a user-determined time point. After addition of the stop reagent, the fluorescence signal remains stable for at least three hours. Custom assay design and packaging are also available.

Amplex™ Red Xanthine/Xanthine Oxidase Assay Kit (Invitrogen™)

The Amplex Red Xanthine/Xanthine Oxidase Assay Kit provides a sensitive and simple fluorometric method for detecting as little as 200 nM xanthine or hypoxanthine or as little as 0.1 mU/mL of xanthine oxidase activity in a purified system with a 100 µL assay volume.