Qubit Protein BR Assay, fluorescent based protein quantitation kit

Fluorescence-based protein quantification detection methods provide superior sensitivity, which means you use less of your protein samples for quantitation and have more samples available for your experiment. In addition, fluorescence-based assays are useful when colorimetric assays cannot be used due to interfering color in the samples. For the assays described below, few steps are required, and timing is not critical so the assays can be adapted for automated handling in high-throughput applications. The fluorescence signal can be detected using a fluorometer or microplate reader.

Protein Assay Selection  Protein Assay Technical Handbook

Choose the right fluorescent protein assay for your sample

  Qubit Protein BR Assay Qubit Protein Assay NanoOrange Protein Quantification Assay CBQCA Protein Quantification Assay EZQ Protein Quantification Assay
Best for Rapid quantitation of small number of samples  Quick quantitation of small number of samples Dilute samples or samples with limited volume Dilute samples or samples with limited volume containing detergents or lipids  High-throughput analysis through solid-phase assay format 
Assay range (sample volume) 100 µg/ml to 20 mg/ml (10–20 µL) 12.5 µg/ml to 5 mg/ml (1–20 µL) 10 ng/mL to 10 µg/mL (up to 10 µL) 10 ng/mL to 150 µg/mL 20 µg/mL to 5 mg/mL (1µL)
Assay incubation time and temperature 10 min at RT 15 min at RT 10 min at 90–95°C 1 hr at RT 1 hr at RT
Detection wavelength (nm) 470/570 470/570 470/570 465/550 280 and 450/618
Required equipment  Qubit 4 Fluorometer Qubit Fluorometer Fluorometer, or fluorescence microplate reader Fluorometer, or fluorescence microplate reader Fluorescence microplate reader, or laser-based scanning systems, or CCD imaging systems
Compatible reagents Detergents, reducing agents, salts Reducing agents, salts Reducing agents, urea, salts Detergents, reducing agents (below 100 µM) Reducing agents, detergents, urea
Incompatible reagents Glycine  Detergents  Detergents  Ammonium salts, amines such as Tris or glycine  
Standard curve 2-point 3-point 5-point 5- to 7-point 5-point
Signal duration 1 hr 3 hr 6 hr 5 hr ---
Mechanism of action Reacts with primary amines found in proteins (N-terminus and epsilon amines found in lysines) Binds to detergent coating on proteins and hydrophobic regions of proteins; the unbound dye is nonfluorescent Binds to detergent coating on proteins and hydrophobic regions of proteins; the unbound dye is nonfluorescent Reacts with primary amine groups on proteins in the presence of cyanide or thiols; the unreacted dye is nonfluorescent Binds electrostatically to basic amino acids, supplemented by additional hydrophobic interactions
Cat. No. A50668
(100 assays)
A50669
(100 assays)
Q33211
(100 assays)
Q33212
(500 assays)
N6666 C6667 R33200

Discover more on how these assays perform in the Molecular Probes Handbook

Pierce Colorimetric Peptide Assay kit components

Need to quantitate peptides?
Try these easy-to-use, accurate, sensitive colorimetric and fluorescent peptide assays:

Choose the right fluorescent protein assay for your sample

  Qubit Protein BR Assay Qubit Protein Assay NanoOrange Protein Quantification Assay CBQCA Protein Quantification Assay EZQ Protein Quantification Assay
Best for Rapid quantitation of small number of samples  Quick quantitation of small number of samples Dilute samples or samples with limited volume Dilute samples or samples with limited volume containing detergents or lipids  High-throughput analysis through solid-phase assay format 
Assay range (sample volume) 100 µg/ml to 20 mg/ml (10–20 µL) 12.5 µg/ml to 5 mg/ml (1–20 µL) 10 ng/mL to 10 µg/mL (up to 10 µL) 10 ng/mL to 150 µg/mL 20 µg/mL to 5 mg/mL (1µL)
Assay incubation time and temperature 10 min at RT 15 min at RT 10 min at 90–95°C 1 hr at RT 1 hr at RT
Detection wavelength (nm) 470/570 470/570 470/570 465/550 280 and 450/618
Required equipment  Qubit 4 Fluorometer Qubit Fluorometer Fluorometer, or fluorescence microplate reader Fluorometer, or fluorescence microplate reader Fluorescence microplate reader, or laser-based scanning systems, or CCD imaging systems
Compatible reagents Detergents, reducing agents, salts Reducing agents, salts Reducing agents, urea, salts Detergents, reducing agents (below 100 µM) Reducing agents, detergents, urea
Incompatible reagents Glycine  Detergents  Detergents  Ammonium salts, amines such as Tris or glycine  
Standard curve 2-point 3-point 5-point 5- to 7-point 5-point
Signal duration 1 hr 3 hr 6 hr 5 hr ---
Mechanism of action Reacts with primary amines found in proteins (N-terminus and epsilon amines found in lysines) Binds to detergent coating on proteins and hydrophobic regions of proteins; the unbound dye is nonfluorescent Binds to detergent coating on proteins and hydrophobic regions of proteins; the unbound dye is nonfluorescent Reacts with primary amine groups on proteins in the presence of cyanide or thiols; the unreacted dye is nonfluorescent Binds electrostatically to basic amino acids, supplemented by additional hydrophobic interactions
Cat. No. A50668
(100 assays)
A50669
(100 assays)
Q33211
(100 assays)
Q33212
(500 assays)
N6666 C6667 R33200

Discover more on how these assays perform in the Molecular Probes Handbook

Pierce Colorimetric Peptide Assay kit components

Need to quantitate peptides?
Try these easy-to-use, accurate, sensitive colorimetric and fluorescent peptide assays:

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