Fluorescent Protein Assays | Thermo Fisher Scientific

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

Peptide quantitation assays

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

Product manuals

Fluorescent 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