Bradford Total Protein Assay Kit (ToPA, K-0014)
Price range: $191.49 through $220.00
The ITSI Total Protein Assay Kit (ToPA) is a high-sensitivity, Bradford-based protein quantification assay optimized for proteomics, biomedical research, molecular biology, biochemistry, and academic laboratory workflows. Designed for rapid, accurate, and reproducible total protein concentration measurement, ToPA supports downstream applications including SDS-PAGE, mass spectrometry (MS), Western blotting, ELISA normalization, enzyme kinetics, and protein expression analysis. The kit comes in two formats, one for use with cuvettes (ToPA-200) and one for use with 96 well plates (ToPA-96).
Total Protein Assay Kit (ToPA) for Proteomics, Biomedical Research & Life Sciences Laboratories
The ITSI Total Protein Assay Kit (ToPA) is a high-sensitivity, Bradford-based protein quantification assay optimized for proteomics, biomedical research, molecular biology, biochemistry, and academic laboratory workflows. Designed for rapid, accurate, and reproducible total protein concentration measurement, ToPA supports downstream applications including SDS-PAGE, mass spectrometry (MS), Western blotting, ELISA normalization, enzyme kinetics, and protein expression analysis.
This ready-to-use colorimetric protein assay delivers enhanced sensitivity, improved buffer compatibility, and consistent linearity (R² > 0.99), making it ideal for cell lysates, tissue lysates, recombinant protein samples, and purified protein preparations.
Optimized for Proteomics & Biomedical Applications
ToPA is specifically engineered for workflows requiring accurate protein normalization prior to:
- SDS-PAGE electrophoresis
- LC-MS/MS and mass spectrometry sample preparation
- Western blot protein loading normalization
- Proteomics sample processing
- Biomarker discovery
- Drug discovery and translational research
- Cell biology and molecular biology assays
- Enzyme activity assays
- Protein purification and recombinant protein analysis
Accurate protein concentration determination is a foundational step in quantitative proteomics and reproducible biomedical research. ToPA simplifies this step while improving sensitivity compared to traditional Bradford protein assays.
High-Sensitivity Bradford-Based Protein Quantification
Based on the Bradford dye-binding method first described by Marion M. Bradford, ToPA uses Coomassie Brilliant Blue G-250 to detect and quantify total protein concentration via absorbance measurement at 595 nm.
Mechanism of Detection
- Acidic dye-binding environment
- Spectral shift from 465 nm (unbound) to 610 nm (protein-bound)
- Optimal absorbance reading at 595 nm
- Signal proportional to basic amino acid content (arginine, lysine, histidine)
- Compatible with proteins ≥ 3 kDa
- Free amino acids and small peptides do not interfere
The result is a rapid, robust, and reproducible Coomassie dye protein assay suitable for both research and preclinical laboratory environments.
Technical Specifications for Laboratory Implementation
- Assay Type: Colorimetric protein assay
- Detection Wavelength: 595 nm
- Sample Type: Protein lysate (cell lysate, tissue lysate, purified protein)
- Minimum Sample Volume: 2 µL
- Assay Time: < 5 minutes per reading
- Linearity: R² > 0.99
Formats Available:
- ToPA-200 (Cuvette format, 200 assays)
- ToPA-96 (96-well microplate format)
ToPA is compatible with standard laboratory equipment including spectrophotometers and microplate readers.
Designed for High-Throughput & Academic Research Labs
Two Workflow Formats
Cuvette-Based Assay (ToPA-200)
- Ideal for small-scale experiments
- Suitable for individual protein samples
96-Well Plate Assay (ToPA-96)
- High-throughput protein quantification
- Optimized for core facilities and proteomics labs
- Streamlined multi-sample processing
Complete Kit Contents for Immediate Implementation
Each ToPA kit includes:
- Quanti-Protein Assay Reagent (Q-PAR)
- Ready-to-Use Standard Curve Reagents
- 2000 µg/mL Standard Curve Reagent (SCR)
- Cuvettes or 96-well microtiter plate
- 1.5 mL assay tubes
- Validated laboratory protocols
The included premade standard curve reagents eliminate time-consuming serial dilutions and improve reproducibility across experiments.
Advantages Over Traditional Bradford Protein Assays
- Increased sensitivity for low-abundance proteins
- Improved tolerance to common laboratory buffers
- Compatible with standard lysis buffers and reducing agents
- Minimal sample volume requirement (2 µL)
- Rapid protein concentration measurement
- Publication-quality reproducibility
- Optimized for proteomics and mass spectrometry workflows
Ideal for Life Sciences, Biotechnology & Translational Research
The ITSI Total Protein Assay Kit (ToPA) supports:
- Academic research laboratories
- Biomedical research institutions
- Biotechnology R&D
- Pharmaceutical development
- Proteomics core facilities
- Clinical and translational research programs
By combining high-sensitivity protein quantification, rapid assay performance, minimal sample input, and validated reproducibility, ToPA enables accurate protein normalization and consistent downstream experimental results in demanding research environments.
Additional information
| Weight | 2 lbs |
|---|---|
| Dimensions | 12 × 9 × 2 in |
| Quantity | 200 Assays, 96 Assays |
Data Sheet(s)
Click on the title(s) below to view the product data sheet.
Citations
Identification of Protein Markers in Patients Infected with Plasmodium knowlesi, Plasmodium falciparum and Plasmodium vivax.
Alan Kang-Wai Mu, Int J Mol Sci. 2014 Nov 3;15(11):19952-61. doi: 10.3390/ijms151119952.
Article Snippet: “After the sample was concentrated to less than 25 μL, 300 μL of ASM Buffer 2 (provided in the kit) was added to the spin column. The sample was again concentrated to a volume less than 25 μL. The ToPA™ assay kit (ITSI Biosciences, Johnstown, PA, USA) was used to determine protein concentrations.”
The effect of selenium enrichment on baker’s yeast proteome.
K. El-Bayoumy, A. Dasa, S. Russell, S. Wolfe, R. Jordan, K. Renganathan, T.P. Loughranb, R. Somiari. Journal of Proteomics-Elsevier Inc. 2011 October 21;.10.1016
Article Snippet: “After homogenization, the samples were incubated on ice for 40 minutes, while vortexing every 10 minutes, and then centrifuged at 13,000xg for 10 minutes at 4°C. The supernatant was transferred to a new tube and the total protein concentration was determined with the ToPA™ total protein assay kit (ITSI – Biosciences, Johnstown, PA) as previously described [20]. Proteins isolated were used for both comparative proteomics and Western blot analysis.”
Selenium-Responsive Proteins in the Sera of Selenium-Enriched Yeast-Supplemented Healthy American and Caucasian Men.
R. Sinha., I. Sinha., N. Facompreruqui., M. Elmissiry. Journal of Biomedical Science. 2009 September;35(3):559-67.
Article Snippet: “The resuspended sample was incubated on ice for 30 minutes, with four vortexes and centrifuged at 15,000 × g for 10 minutes. The supernatant was transferred to a fresh tube and placed on ice until analyzed on the same day. Total protein content was determined with the ToPA protein assay kit and Bradford protocol (ITSI Biosciences) using bovine serum albumin as a standard.”
Proteomics of rat prostate lobes treated with 2-N-Hydroxylamino-1-methyl-6-phenylimidazo [4,5-b] pyridine, 5alpha-dihydrotestosterone, individually and in combination.
Boyiri, T., Somiari, RI., Russell, S., EL-Bayoumy, K. Int. J Oncol. 2009 Sep;35(3):559-67
Article Snippet: “After homogenization samples were incubated on ice for 30 min, with 4 vortexes, and centrifuged at 16,000 × g for 10 min. The supernatant was transferred to a fresh tube and placed on ice until analysis on the same day. Total protein concentration of each sample was determined with the ToPA™ protein assay kit (ITSI-Biosciences) using the Bradford protocol and bovine serum albumin as standard.”
Q & A
Bradford Total Protein Assay Kit (ToPA, K-0014)
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