| |
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.
