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EnzChek™ Protease Assay Kit, red fluorescence, 100-1000 assays (Invitrogen™)

The EnzChek® Protease Assay Kit, red fluorescence, is a fast, simple, and direct fluorescence-based assay for detecting metallo-, serine, acid, and sulfhydryl proteases. The accompanying increase in fluorescence, which can be measured with a fluorescence microplate reader, is proportional to protease activity.

See our complete line of Fluorescence Microplate assays.

• Generalized mechanism allows for measurement of a variety of proteases
• Can be used to continuously measure protease kinetics
• Excitation/emission similar to Texas Red® dye (589/617 nm)

This EnzChek® Protease Assay Kit contains a casein derivative that has been extensively labeled with the red-fluorescent BODIPY® TR-X dye, which results in a quenching of the fluorescent dye. Protease-catalyzed hydrolysis releases the highly-fluorescent BODIPY® TR-X dye-labeled peptides, allowing for quantitative detection of protease activity in solution. The red-fluorescent BODIPY® TR-X dye has excitation and emission spectra similar to those of the Texas Red® fluorophore.

Pierce™ Fluorescent Protease Assay Kit (Thermo Scientific™)

The Thermo Scientific Pierce Fluorescent 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 includes fluorescein-labeled casein as a substrate for assessing protease activity in a sample by either fluorescence resonance energy transfer (FRET) with a standard fluorometer or fluorescence polarization (FP) with capable instrumentation. FTC-Casein is native casein that has been labeled using a large molar excess of fluorescein isothiocyanate (FITC). Fluorescence properties of this heavily-labeled, intact protein substrate change dramatically upon digestion by proteases, resulting in a measurable indication of proteolysis.

Features of the Fluorescent 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: fluorescein-labeled casein (FITC-casein); available separately as Part No. 23267
• Basis of assay: change in fluorescence resonance (FRET) or fluorescence polarization (FP)
• Measurement: instrument with fluorescein excitation and emission filters (485/538nm)

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

Pierce™ Renilla Luciferase Glow Assay Kit (Thermo Scientific™)

The Thermo Scientific Pierce Renilla Luciferase Glow Assay Kit provides an extremely bright and stable bioluminescence signal (half-life approx. 3 hours), especially in the presence of Green Renilla luciferase reporter.

Features of the Renilla Luciferase Glow Assay Kit:

Sensitive—highly sensitive detection of Green Renilla luciferase activity
Stable—increased signal stability compared to flash assays
Simple—does not require a luminometer with injectors
Compatible—assay reagents compatible with other Renilla luciferases
Automation-friendly—amenable to high throughput assays
Convenient—contains a universal cell lysis buffer and optimized glow assay reagent
Safe—allows one to perform non-radioactive assays

This Pierce Luciferase Glow Assay Kit contains reagents for measuring the activity of Renilla luciferase in cell lysates. In the presence of luciferase, the glow reagent provides stable bioluminescent signal and is highly suited for luminometers without injectors or for batch processing of samples. The light output generated by the luciferase reaction can be correlated with the amount of luciferase protein produced which in turn is proportional to the promoter activity driving the luciferase expression. The glow assay reagents were optimized for best results with Thermo Scientific Green Renilla Luc Plasmids; however, this glow kit may be used to detect the activity of other Renilla luciferase derivatives that use coelenterazine as a substrate.

Includes:
Cell lysis buffer, reaction buffer and substrate

Requires:
Renilla luciferase and luminometer or other instrument capable of monitoring luminescence, such as Thermo Scientific Luminoskan Ascent and Varioskan Flash Microplate Readers.

Applications:
• Promoter studies for analyzing cis- regulatory elements and trans-acting factors
• Drug screening
• siRNA and miRNA screening
• Multiplexed assays to study off-target effects
• Protein localization reporter assays
• Signal transduction pathway analysis
• RNA splicing studies

The Green Renilla luciferase is a 36kDa protein produced by a derivative of the wild type Renilla luciferase gene from the sea pansy, Renilla reniformis. Compared to the wild type luciferase, Green Renilla is more stable in serum and has an the emission spectrum that is shifted toward the green region. The protein provides extremely bright flash signal that decays rapidly. The Pierce Renilla Glow Assay Kit reagent effectively stabilizes this bright bioluminescence to yield a signal half-life greater than 3 hours, thus eliminating the need for a luminometer with injectors. The assay kit was optimized for best results with Thermo Scientific Green Renilla Luc Plasmids; however, this glow kit may be used to detect the activity of other Renilla luciferase derivatives that use coelenterazine as a substrate.

Related Products
Pierce™ Renilla-Firefly Luciferase Dual Assay Kit

FITC-Casein for Pierce™ Fluorescent Protease Assay Kit (Thermo Scientific™)

FTC-Casein, 2.5 mg, lyophilized, FRET/FP Certified Grade, for use with the Pierce Fluorescent Quantitative Protease Assay Kit.

Related Products
Pierce™ Colorimetric Protease Assay Kit
Pierce™ Fluorescent Protease Assay Kit

Phosphate Sensor

The Phosphate Sensor is a highly sensitive reagent for the detection of inorganic phosphate, either in real-time kinetic or end-point mode. This product is a purified form of recombinant E. coli phosphate-binding protein labeled with the fluorophore MDCC, which is sensitive to changes in its environment. Binding of inorganic phosphate by Phosphate Sensor is rapid and tight (Kd ~ 0.1 µM), resulting in a large increase in fluorescence. The Phosphate Sensor detects phosphate in the high-nanomolar to low-micromolar range, which is 100-fold more sensitive than malachite green. This reagent provides you with a sensitive assay for detecting enzymes that produce inorganic phosphate either directly or indirectly through coupled reactions, such as phosphatases, ATPases, GTPases, and phosphodiesterases.

Catalase Colorimetric Activity Kit (Invitrogen™)

The Catalase Activity research-use-only kit is a colorimetric activity assay designed for the quantification and detection of catalase activity in serum, plasma, cells, tissues and erythrocyte lysates.

This complete, ready-to-use kit includes clear 96 well plate(s), catalase standard (100 Unit/mL), catalase substrate, and other components to perform the assay. A 96-well microplate reader capable of reading optical density at 560 nm (acceptable range: 540-580 nm) is required for use of this kit.

Performance characteristics
• Assay type: colorimetric activity kit
• Sample types: serum, plasma, cells, tissues, and erythrocyte lysates.
• Sensitivity: 0.052 U/mL
• Standard curve range: 0.15 U/mL–5.0 U/mL
• Reactivity: species independent

Background
Hydrogen peroxide is one of the most frequently occurring reactive oxygen species. It is formed either in the environment or as a by-product of aerobic metabolism, superoxide formation and dismutation, or as a product of oxidase activity. Both excessive hydrogen peroxide and its decomposition product hydroxyl radical, formed in a Fenton-type reaction, are harmful for most cell components. Its rapid removal is essential for all aerobically living prokaryotic and eukaryotic cells. However, hydrogen peroxide can act as a second messenger in signal transduction pathways, in immune cell activation, inflammation processes, cell proliferation, and apoptosis.

One of the most efficient ways of removing peroxide is through the enzyme catalase, which is encoded by a single gene and is highly conserved among species. Mammals, including humans and mice, express catalase in all tissues, and a high concentration of catalase can be found in the liver, kidneys, and erythrocytes. The expression is regulated at transcription, post-transcription, and post-translation levels. High catalase activity is detected in peroxisomes. More recently, short wavelength UV radiation has been shown to produce reactive oxygen species (ROS) through the action of catalase. This response is thought to act as a mechanism to protect DNA by converting damaging UV radiation into ROS species that can be metabolized and detoxified by cellular antioxidant enzymes. This assay has been validated for serum, EDTA and heparin plasmas from a variety of species.

Assay principle
The Catalase Activity kit is designed to quantitatively measure catalase activity in a variety of samples. A bovine catalase standard is provided to generate a standard curve for the assay and all samples should be read off of the standard curve. Samples are diluted in the provided Assay Buffer and added to the wells of a half area clear plate. Hydrogen peroxide is added to each well and the plate incubated at room temperature for 30 minutes. The supplied Colorimetric Detection Reagent is added, followed by diluted horseradish peroxidase, and incubated at room temperature for 15 minutes. The HRP reacts with the substrate in the presence of hydrogen peroxide to convert the colorless substrate into a pink-colored product. The colored product is read at 560 nm. Increasing levels of catalase in the samples causes a decrease in hydrogen peroxide concentration and a reduction in pink product.

Catalase unit definition
One unit of Catalase decomposes one micromole of hydrogen peroxide per minute at 25°C and pH 7.0.

Related links
Learn more about ELISA kits
Learn more about other immunoassays

EnzChek™ Phospholipase A2 Assay Kit (Invitrogen™)

This kits takes our stand alone assay for phospholipase A2, PLA2 (A10072) and combines the necessary Ez and lipids to run 2 complete 96 well microplate assays that monitor activity in purified enzyme preparations and cell lysates. The EnzChek Phospholipase A2 Kit provides enough reagents for 2 microplates, using 200 µl volumes in 96 well format to perform continuous fluorometric monitoring of PLA2 . This product offers an alternative to our (B7701), (bis-BODIPY® FL C11-PC) reagent, by providing an PLA2 selective substrate and one that is ratiometric, thereby lowering variations produced by instrumentation and assay conditions. Phospholipase A2 or PLA2 represents a family of enzymes that hydrolyze the sn-2 ester linkage of phospholipids. The activities of these enzymes play important roles in cardiovascular, inflammatory and nervous system disorders, and in cancers. The EnzChek® Phospholipase A2 substrate provides sensitive and continuous rapid real-time monitoring of PLA2 enzyme activities. This unique substrate is selective for PLA2 and can be used either in a intensity or ratiometric based detection mode. In intensity based detection mode the PLA2 activity is monitored by the intensity increase of a single wavelength at approximately 515 nm. In ratiometric analysis, which is based on the distinct fluorescence resonance energy transfer (FRET) emission of this substrate prior to and after cleavage, PLA2 is detected by changes in the emission intensity ratio at 515/575 nm with excitation at ≈ 460 nm. Either detection mode provides a simple method with low background, high sensitivity and high specificity for PLA2.

Acetylcholinesterase Fluorescent Activity Kit (Invitrogen™)

The Acetylcholinesterase Fluorescent Activity research-use-only kit is a fluorescent activity assay designed for the quantification and detection of acetylcholinesterase activity in serum, plasma, and erythrocyte membrane samples.

This complete, ready-to-use kit includes black 96-well plate(s), acetylcholinesterase standard (1,000 mU/mL), acetylcholinesterase substrate, acetylthiocholine iodide, and other components to perform the assay. A fluorescence 96-well microplate reader capable of reading fluorescent emission at 510 nm, with excitation at 390 nm, is required for use of this kit.

Performance characteristics
• Assay type: fluorescent activity kit
• Sample types: serum, plasma, and erythrocyte membrane samples
• Sensitivity: 0.218 mU/mL
• Standard curve range: 6.25 mU/mL–100 mU/mL
• Reactivity: species independent

Background
Acetylcholine (ACh) is an essential neurotransmitter in the central and peripheral nervous systems. In the brain multiple areas exist where cholinergic neurons are concentrated. Nicotinic and muscarinic ACh receptors are recognized as binding and effector proteins to mediate chemical neurotransmission at neurons, ganglia, heart, and smooth muscle fibers and glands.

Acetylcholinesterase is encoded by the single AChE gene; the structural diversity in the gene products arises from alternative mRNA splicing and post translational associations of catalytic and structural subunits. The major form of acetylcholinesterase found in brain, muscle, and other tissues is the hydrophilic species, which forms disulfide-linked oligomers with collagenous, lipid-containing structural subunits. The other alternatively-spliced form, expressed primarily in the erythroid tissues, is structurally different at the C-terminal end and contains a cleavable peptide with a GPI anchor. It associates with membrane receptors through phosphoinositide moieties added post-translationally. This assay has been validated for serum, EDTA and heparin plasma, and solubilized RBC ghosts from a variety of species.

Assay principle
The Acetylcholinesterase Activity kit is designed to quantitatively measure acetylcholinesterase activity in a variety of samples. A human AChE standard is provided to generate a standard curve for the assay and all samples should be read off the standard curve. The kit utilizes a proprietary non-fluorescent molecule, that covalently binds to the thiol product of the reaction between the AChE Substrate and AChE in the standards or samples, yielding a fluorescent product read at 510 nm in a fluorescent plate reader with excitation at 390 nm. The kit is suitable for measuring AchE activity in appropriately diluted serum, plasma, and RBC ghosts from a number of species. It will also measure AChE in extracted tissue samples and cell lysates.

AChE unit definition
One unit will hydrolyze 1.0 μmol of acetylthiocholine iodide per minute at pH 7.4 and 37˚C.

Related links
Learn more about ELISA kits
Learn more about other immunoassays

Z'-LYTE™ Kinase Assay Kit - Ser/Thr 17 Peptide

A coumarin and fluorescein-labeled peptide substrate which can be used for kinase screening in an antibody-free format. This peptide is based upon glycogen synthase, containing Ser-7.

Kinase Tracer 222, 50 µM

Kinase Tracer 222 is an Alexa Fluor® 647 dye-labeled, ATP-competitive kinase inhibitor scaffold for use in the LanthaScreen® Eu Kinase Binding Assay.

The LanthaScreen® Eu Kinase Binding Assay
Is easily optimized
Measures inhibitor binding
Performs simple off-rate measurements

Easily Screen for Kinase Binding
The LanthaScreen® Eu Kinase Binding Assay is a TR-FRET assay that lets you measure inhibitor binding to non-activated kinases, perform simple off-rate measurements, and makes simple the study of type III (allosteric) inhibitors.

The LanthaScreen® Eu Kinase Binding Assay is easy to optimize and run. The assay uses a simple mix-and-read format with a single one hour incubation and no development steps. Binding of an Alexa Fluor® conjugate or “tracer” to a tagged kinase is detected by addition of a europium-labeled anti-tag antibody, in this case anti-GST. Simultaneous binding of the tracer and antibody to the kinase results in a high degree of fluorescence resonance energy transfer (TR-FRET), while displacement of the tracer with a kinase inhibitor results in a loss of TR-FRET.

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

Related Link
•  Learn more about the LanthaScreen® Eu Binding Assay.

Z'-LYTE™ Kinase Assay Kit - Tyrosine 1 Peptide

A coumarin and fluorescein-labeled peptide substrate which can be used for kinase screening in an antibody-free format. This peptide is based upon an optimal peptide substrate for SRC.

Pierce™ Firefly Luciferase Glow Assay Kit (Thermo Scientific™)

The Thermo Scientific Pierce Firefly Luciferase Glow Assay Kit provides a bright and stable bioluminescence signal (half-life greater than 2 hours) in the presence of firefly luciferase reporters for protein expression assays.

Features of the Firefly Luciferase Glow Assay Kit:

Sensitive—highly sensitive detection of firefly luciferase activity; for best results (maximum signal) use with Pierce Firefly Luciferase Signal Enhancer
Stable—increased signal stability compared to flash assays
Simple—does not require a luminometer with injectors
Compatible—assay reagents compatible with other firefly beetle luciferases
Automation-friendly—amenable to high throughput assays
Convenient—contains a universal cell lysis buffer and optimized glow assay reagent
Safe—allows one to perform non-radioactive assays

This Pierce Luciferase Glow Assay Kit contains reagents for measuring the activity of firefly luciferase in cell lysates. In the presence of firefly luciferase, the glow reagent provides stable bioluminescent signal and is highly suited for luminometers without injectors or for batch processing of samples. The light output generated by the luciferase reaction can be correlated with the amount of luciferase protein produced which in turn is proportional to the promoter activity driving the luciferase expression. The glow assay reagents were optimized for best results with Thermo Scientific Firefly Luc Plasmids; however, this assay kit may be used to detect the activity of other firefly or ATP-dependent luciferases that use D-luciferin as a substrate.

Includes:
Cell lysis buffer, reaction buffer and substrate; purchase Luciferase Signal Enhancer separately.

Requires:
• Firefly luciferase and luminometer or other instrument capable of monitoring luminescence, such as Thermo Scientific Luminoskan Ascent and Varioskan Flash Microplate Readers.
• For best results (maximum signal), use with Pierce Firefly Luciferase Signal Enhancer

Applications:
• Promoter studies for analyzing cis- regulatory elements and trans-acting factors
• Drug screening
• siRNA and miRNA screening
• Multiplexed assays to study off-target effects
• Protein localization reporter assays
• Signal transduction pathway analysis
• RNA splicing studies

Firefly luciferase is a 60kDa protein produced in nature by several species of the Lampyridae family of beetles which includes the genera Photinus and Luciola. Bioluminescent signal from firefly luciferase originates from the oxidation of D-luciferin. Light output generated by the luciferase reaction is captured using a luminometer and can be correlated with the amount of firefly luciferase protein produced and used to determine the activity of the promoter driving firefly expression. The native firefly luciferase produces a strong flash signal that decays rapidly. The signal produced using the Pierce Firefly Glow Assay Kit is more stable and decays very slowly, thereby eliminating the need for a luminometer with injectors.

Pierce™ Firefly Luc One-Step Glow Assay Kit (Thermo Scientific™)

The Thermo Scientific Pierce Firefly One-Step Luc Glow Assay Kit measures firefly luciferase activity in mammalian cell culture using a single reagent-addition step, making it ideal for high-throughput screening (HTS) applications.

Features of the Firefly One-Step Luc Glow Assay Kit:

Sensitive—highly sensitive detection of firefly luciferase activity
Odorless—reagents have no foul or toxic odor, eliminating the need to work in a fume hood
Convenient—one-step, mix-and-read protocol; no additional reagents required
Stable—increased signal half-life and stability compared to flash assays
Simple—does not require a luminometer with injectors
Automation-friendly—amenable to high throughput assays

This glow-type luciferase assay kit is designed for use with cultured mammalian cells that are transfected with vectors expressing the appropriate firefly luciferase reporter enzyme. Several features make the kit especially suitable for luminometers without injectors and for high-throughput screening (HTS) applications. The convenient, one-step, homogenous protocol minimizes handling steps to support the use of automation. Simply combine the supplied substrate solution and assay buffer to make a single working solution, and then add it to microplate wells containing the transfected, treated cells. The stable signal output (glow) of this system provides flexibility with regard to incubation time. When used with Thermo Scientific Firefly Luc Plasmids, the kit provides a highly sensitive bioluminescent reporter assay system for the detection of promoter or pathway activity.

Includes:
Assay buffer and substrate solution (100X)

Requires:
Firefly luciferase and luminometer or other instrument capable of monitoring luminescence, such as Thermo Scientific Luminoskan Ascent and Varioskan Flash Microplate Readers.

Applications:
• Promoter studies for analyzing cis- and trans-acting regulatory elements
• Drug screening
• siRNA and miRNA screening
• Multiplexed assays to study off-target effects
• Protein localization reporter assays
• Signal transduction pathway analysis

Firefly luciferase is a 62kDa protein produced in nature by several species of the Lampyridae family of beetles, which includes the genera Photinus and Luciola. Thermo Scientific Red Firefly Luciferase has an emission range of 560-700nm (λmax = 613nm). Bioluminescent signal from firefly luciferase originates from the oxidation of D-Luciferin. Light output captured using a luminometer can be correlated with the amount of firefly luciferase protein produced and used to determine the activity of the promoter driving firefly luciferase expression. Firefly luciferase bioluminescence provides researchers with a non-radioactive assay for measuring transcriptional activity of regulatory elements. Firefly luciferase reporter activity can be used to determine promoter activity, to study upstream pathway activity in the cell, or to determine effect of activators or inhibitors.

Z'-LYTE™ Kinase Assay Kit - Ser/Thr 13 Peptide

A coumarin and fluorescein-labeled peptide substrate which can be used for kinase screening in an antibody-free format. This peptide is based upon myosin light chain 2, containing Ser-20 and a Hyd-X-R-X-X-(S⁄T) consensus sequence, where Hyd is a hydrophobic residue and X is any residue.

EnzChek™ Gelatinase/Collagenase Assay Kit, 250-2,000 assays (Invitrogen™)

The EnzChek Gelatinase/Collagenase Assay Kit provides a sensitive, convenient and fast fluorometric method for measuring gelatinase or collagenase activity in purified enzyme systems, cell/tissue lysates or for screening inhibitors in a high-throughput format. The substrate in the EnzChek kit is our fluorescein-labeled DQ gelatin conjugate that is highly labeled so that the fluorescence signal is quenched until enzymatic digestion yields highly fluorescent fragments. This substrate is also available separate from the kit (D-12054).