Quick Start™ Bradford Protein Assay

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Overview

Protein Assay Comparison
Characteristics of Bio-Rad's Protein Assays
  Protein Assay
Quick Start™ Bradford Bio-Rad DC RC DC™
Adapted from method of Bradford (1976) Bradford (1976) Lowry et al. (1951) Lowry et al. (1951)
Standard concentration assay        
Sample volume 100 µl 100 µl 100 µl 100 µl
Linear range 0.125–1.5 mg/ml 0.2–1.5 mg/ml 0.125–1.5 mg/ml 0.125–1.5 mg/ml
Low-concentration assay        
Sample volume 1 ml 800 µl 200 µl 200 µl
Linear range 1.25–25 µg/ml 1.25–25 µg/ml 5–250 µg/ml 5–250 µg/ml
Microplate assay sample volume 5 µl 10 µl 5 µl *
Minimum incubation time 5 min 5 min 15 min 15 min
Assay wavelength 595 nm 595 nm 650–750 nm 650–750 nm

All assays are easy to use, require little reagent preparation, and give accurate and reproducible results.

* To adapt the RC DC assay to a microplate format, follow the micro test tube (microfuge tube) assay protocol in the RC DC instruction manual up to the centrifugation step where the supernatant is discarded. The pellet can then be transferred to the microplate, and the microplate assay protocol in the DC protein assay manual can be followed.

In a typical protein assay, a chemical reagent is added to a protein sample, producing a visible result, such as a color change in the sample solution. This color change is quantitated with a spectrophotometer or microplate reader, and compared to a standard curve of known concentrations of protein versus their absorbance after reaction with the reagent. The amount of protein in the unknown sample is determined by interpolation, reading the concentration of protein on the standard curve that corresponds to its absorbance.

Protein Assay Selection Guide

Chart RC DC Protein Assay DC Protein Assay Quick Start Bradford Assay Assay Bio-Rad Protein Assay

  * Nonidet P-40 >0.25%, Triton C-100 >0.05%, Tween 20 >0.01%, SDS >0.025%
** DTT >1 mM, EDTA >1 mM

Compatible Reagents*
Acetone, 10%
EGTA, 0.2 M
Nonidet P-40 (NP-40), 0.25%
Sodium hydroxide, 0.1 M
Acetonitrile, 10%
Ethanol, 10%
Octyl-β-glucoside, 0.5%
Sodium phosphate, 0.5 M
Ammonium sulfate, 1 M
Glucose, 20%
Octyl β-thioglucopyranoside, 1%
Sucrose, 10%
Ampholytes, pH 3–10, 0.5%
Glycerol, 5%
PBS
TBS, 0.5x (12.5 mM Tris, 75 mM NaCl, pH 7.6)
ASB-14, 0.025%
Glycine, 0.1 M
Phenol red, 0.5 mg/ml
TCEP, 20 mM
Ascorbic acid, 50 mM
Guanidine-HCl, 2 M
PIPES, 0.2 M
Thiourea, 1 M
Bis-Tris, pH 6.5, 0.2 M
Hank's salt solution
PMSF, 2 mM
Tributylphosphine (TBP), 5 mM
Calcium chloride, 40 mM
HCl, 0.1 M
Potassium chloride, 2 M
Tricine, pH 8, 50 mM
CHAPS, 10%
HEPES, 0.1 M
Potassium phosphate, 0.5 M
Triethanolamine, pH 7.8, 50 mM
CHAPSO, 10%
Imidazole, 0.2 M
SB 3-10, 0.1%
Tris, 1 M
Deoxycholic acid, 0.2%
Magnesium chloride, 1 M
SDS, 0.025%
Tris-glycine (25 mM Tris, 192 mM glycine)
Dithioerythritol (DTE), 10 mM
β-Mercaptoethanol, 1 M
Sodium acetate, pH 4.8, 0.2 M
Tris-glycine-SDS, 0.25x (6.25 mM Tris, 48 mM glycine, 0.025% SDS)
Dithiothreitol (DTT), 10 mM
MES, 0.1 M
Sodium azide, 0.5%
Triton X-100, 0.05%
DMSO, 5%
Methanol, 10%
Sodium bicarbonate, 0.2 M
Tween 20, 0.01%
Eagle's MEM
Modified Dulbecco's PBS
Sodium carbonate, 0.1 M
Urea, 4 M
Earle's salt solution
MOPS, 0.1 M
Sodium chloride, 2.5 M
EDTA, 0.2 M
NAD, 2 mM
Sodium citrate, pH 4.8 or 6.4, 0.2 M
* Concentrations compatible with the microassays are 1/25 of the values listed above.

The Quick Start™ Bradford protein assay is a simple and accurate procedure for determining the concentration of protein in solution. The assay supplies ready-to-use dye reagent at 1x concentration and two protein standards at seven prediluted concentrations (0.125, 0.25, 0.5, 0.75, 1.0, 1.5, and 2.0 mg/ml). Protein concentration is determined in one step, with no need to dilute standards. Quick Start Bradford protein assay kits offer either bovine serum albumin or bovine γ-globulin standard sets.

Standard-concentration assay  
Sample volume 100 µl
Linear range 0.125-1.5 mg/ml
Low-concentration assay  
Sample volume 1 ml
Linear range 1.25-25 µg/ml
Assay wavelength 595 nm
Minimum incubation time 5 min
Adapted from method of Bradford
Quick Start™ Bradford Protein Assay Kit 1

500-0201
Colorimetric assay kit, includes 1x dye reagent (1 L), BSA standard (5 x 2 mg/ml); 200 standard assays or 4,000 microplate assays

List Price:   $137.00
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Quick Start™ Bradford Protein Assay Kit 2

500-0202
Colorimetric assay kit, includes 1x dye reagent (1 L), BSA standard set (2 sets of 7 standards, 0.125–2.0 mg/ml, 2 ml)

List Price:   $176.00
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Quick Start™ Bradford Protein Assay Kit 3

500-0203
Colorimetric assay kit, includes 1x dye reagent (1 L), bovine γ-globulin standard (5 x 2 mg/ml)

List Price:   $143.00
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Quick Start™ Bradford Protein Assay Kit 4

500-0204
Colorimetric assay kit, includes 1x dye reagent (1 L), bovine γ-globulin standard set (2 sets of 7 standards, 0.125–2.0 mg/ml, 2 ml)

List Price:   $181.00
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Number Description Options
1123 Protein Assay Applications Bibliography Click to download
1069 Colorimetric Protein Assays, Rev D Click to download [ Add to Cart (Free) ]
2969 Quick Start Bradford Protein Assay Product Information Sheet, Rev A Click to download
4110065 Instruction Manual, Quick Start Bradford Protein Assay, Rev A Click to download [ Add to Cart (Free) ]