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

The EnzChek® Protease Assay Kit, green 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 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 of 505/513 nm allows use of standard fluorescein (FITC) filter settings

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

EnzChek™ Peptidase/Protease Assay Kit (Invitrogen™)

The EnzChek® Peptidase/Protease Assay Kit enables simple and accurate quantification of a wide range of protease activities within 60 minutes.

See our complete line of Fluorescence Microplate assays.

• Simple mix-incubate-read format
• Excitation and emission wavelengths (502/528 nm) well suited for fluorescein (FITC) filter settings
• Easily adapted to a variety of proteases and reaction conditions

The EnzChek® peptidase/protease substrate included in the kit has been labeled with a fluorophore and a quencher moiety separated by a peptide. Upon cleavage by protease(s), the fluorophore separates from the quencher and, upon excitation, the fluorophore emits fluorescence signal. The magnitude of the resultant signal is proportional to the degree of substrate cleavage, resulting in an ability to quantify the amount of enzyme activity. The assay is performed in a simple mix–incubate–read format, can be completed in 60 minutes or less, and is easily adapted to accommodate diverse pH requirements.

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

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™ 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

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