Biuret Protein Colorimetric Assay Kit
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Biuret Protein Colorimetric Assay Kit
| SKU # | E-BC-K165-M |
| Detection Instrument | Microplate reader (520-580 nm, optimum wavelength: 540 nm) |
| Detection method | Colorimetric method |
Product Details
Properties
| Synonyms | TP |
| Sample Type | Serum, plasma, tissue |
| Sensitivity | 0.58 g/L |
| Detection Range | 0.58-100 g/L |
| Detection Method | Colorimetric method |
| Assay type | Quantitative |
| Assay time | 20 min |
| Precision | Average inter-assay CV: 6.500% | Average intra-assay CV: 4% |
| Other instruments required | Micropipettor, Incubator, Vortex mixer, Centrifuge |
| Other reagents required | Normal saline (0.9% NaCl), PBS (0.01 M, pH 7.4) |
| Storage | Reagent 3: -20℃, others: 2-8℃ |
| Valid period | 12 months |
Images
A A-R Mohamed et al found that selenium nanoparticle can alleviate cardio-hepatic damage in type II diabetes. Total protein (TP) level in rat serum was determined using biuret protein colorimetric assay kit (E-BC-K165-M).
Table. Effect of different treatments (metformin at a dose of (500 mg/kg) and /or CTS-Se-NPs (2 mg Se/kg per day) in HFD/STZ diabetic rats on glucose level, insulin, lipid profile and hepatic oxidative stress.
| Control | HFD/STZ | STZ+MET | STZ+CTS-SeNPs | STZ+MET+CTs-SeNPs | |
| TP (g/dl) | 7.17±.07 c | 2.85±12 a | 5.31±.07 b | 5.41±.08 b | 6.88±.11 c |
| Albumin (g/dl) | 3.45±.06 c | 1.39±.03 a | 2.59±.11 b | 2.65±.04 b | 3.44±.06 c |
TP level was significantly induced in HFD/STZ treated group.
Dilution of Sample
It is recommended to take 2~3 samples with expected large difference to do pre-experiment before formal experiment and dilute the sample according to the result of the pre-experiment and the detection range (0.58-100 g/L).
The recommended dilution factor for different samples is as follows (for reference only):
| Sample type | Dilution factor |
| Human serum | 1 |
| Human plasma | 1 |
| Rat serum | 2-4 |
| Mouse plasma | 1 |
| Rabbit serum | 1 |
| Chicken plasma | 1 |
| Horse serum | 1-3 |
| Porcine serum | 1-3 |
| Dog serum | 2-4 |
| 10% Rat spleen tissue homogenate | 1 |
| 10% Mouse liver tissue homogenate | 1 |
| 10% Mouse kidney tissue homogenate | 1 |
Note: The diluent is normal saline (0.9% NaCl) or PBS (0.01 M, pH 7.4).
Detection Principle
Any compound that contains two -CONH2 in the molecule can react with alkaline copper solution to form a purple complex, which is known as the biuret reaction. Many peptide bonds (-CONH-) in protein molecules can perform this reaction, and the color degree of all kinds of proteins are essentially the same.
Kit Components & Storage
| Item | Component | Size 1 (96 T) | Size 2 (500 Assays) | Storage |
| Reagent 1 | Copper Reagent | Powder × 1 vial | Powder × 5 vials | 2-8°C, 12 months |
| Reagent 2 | Alkali | Powder × 1 vial | Powder × 5 vials | 2-8°C, 12 months, shading light |
| Reagent 3 | 100 g/L Protein Standard | 1 mL × 1 vial | 1 mL × 5 vials | -20°C, 12 months |
| Microplate | 96 wells | No requirement | ||
| Plate Sealer | 2 pieces | |||
Note: The reagents must be stored strictly according to the preservation conditions in the above table. The reagents in different kits cannot be mixed with each other. For a small volume of reagents, please centrifuge before use, so as not to obtain sufficient amount of reagents.
Technical Data:
Parameter:
Intra-assay Precision
Three human serum samples were assayed in replicates of 20 to determine precision within an assay. (CV = Coefficient of Variation)
| Parameters | Sample 1 | Sample 2 | Sample 3 |
| Mean (g/L) | 2.50 | 38.50 | 95.00 |
| %CV | 4.2 | 3.4 | 4.4 |
Inter-assay Precision
Three human serum samples were assayed 20 times in duplicate by three operators to determine precision between assays.
| Parameters | Sample 1 | Sample 2 | Sample 3 |
| Mean (g/L) | 2.50 | 38.50 | 95.00 |
| %CV | 6.2 | 7.5 | 5.8 |
Recovery
Take three samples of high concentration, middle concentration and low concentration to test the samples of each concentration for 6 times parallelly to get the average recovery rate of 98%.
| Standard 1 | Standard 2 | Standard 3 | |
| Expected Conc. (g/L) | 15 | 56 | 72 |
| Observed Conc. (g/L) | 15.2 | 52.6 | 71.3 |
| Recovery rate (%) | 101 | 94 | 99 |
Sensitivity
The analytical sensitivity of the assay is 0.58 g/L. This was determined by adding two standard deviations to the mean O.D. obtained when the zero standard was assayed 20 times, and calculating the corresponding concentration.
Standard Curve
As the OD value of the standard curve may vary according to the conditions of the actual assay performance (e.g. operator, pipetting technique or temperature effects), so the standard curve and data are provided as below for reference only:
| Concentration (g/L) | 0 | 10 | 20 | 40 | 50 | 60 | 80 | 100 |
| OD value | 0.122 | 0.155 | 0.189 | 0.255 | 0.289 | 0.323 | 0.391 | 0.463 |
| 0.122 | 0.156 | 0.191 | 0.257 | 0.290 | 0.324 | 0.393 | 0.465 | |
| Average OD | 0.122 | 0.156 | 0.190 | 0.256 | 0.290 | 0.324 | 0.392 | 0.464 |
| Absoluted OD | 0.000 | 0.034 | 0.068 | 0.134 | 0.168 | 0.202 | 0.270 | 0.342 |