- Home
- IVD
- By Technology Types
- By Diseases Types
- By Product Types
- Research
- Resource
- Distributors
- Company
| Product Name | Lowry Protein Assay Kit, Modified (Peterson's Method) |
| Catalog No. | PTR-HMM-0087 |
| Description | Modified Lowry protein assay kit based on Peterson's modification incorporating SDS for membrane protein solubilization and sodium deoxycholate-TCA protein precipitation for removal of interfering substances. The classic Lowry chemistry (Biuret reaction + Folin-Ciocalteu phosphomolybdic-tungstic acid reduction) provides high sensitivity with less protein-to-protein variation than Coomassie dye-binding methods. Includes a protein precipitation step to eliminate interference from detergents, reducing agents, and other common buffer components. |
| Intended Use | Quantitative total protein determination in cell and tissue lysates; protein quantification for SDS-PAGE loading; protein determination in samples containing detergents (SDS, Triton X-100, NP-40) and reducing agents (DTT, β-mercaptoethanol); membrane protein quantification. |
| Principle / Technology | Step 1 (Biuret): Cu²⁺ complexes with peptide bonds in alkaline conditions; Step 2 (Folin-Ciocalteu): phosphomolybdic-tungstic acid heteropoly acids are reduced by Cu⁺-protein complex and aromatic amino acids (Tyr, Trp) to heteropolymolybdenum blue (A750); precipitation step (DOC-TCA) removes interfering substances before assay |
| Detection Method | Colorimetric; absorbance at 750 nm; standard curve 0-100 µg BSA; DOC-TCA precipitation for samples with interfering substances |
| Sample Type | Protein solutions (1-50 µL, containing 1-100 µg protein); cell/tissue lysates; samples with up to 5% SDS, 1% Triton X-100, 100 mM DTT after precipitation |
| Sensitivity / LOD | Linear range 1-100 µg BSA per assay (standard protocol); 0.2-20 µg per assay (micro protocol); detection limit ~0.5 µg/mL protein |
| Specificity | Measures total protein (peptide bonds and Tyr/Trp residues); less protein-to-protein variation than Coomassie (Bradford); Folin reagent reacts with many reducing substances — precipitation step removes most interferents |
| Reaction Conditions / Protocol | For standard protocol: add 100 µL sample + 100 µL Cu-tartrate-carbonate reagent; incubate 10 min RT; add 500 µL diluted Folin-Ciocalteu reagent; incubate 30 min RT; read A750; for precipitation protocol: add DOC then TCA to precipitate protein; wash pellet; redissolve in SDS; proceed with standard protocol |
| Components / Formulation | Cu-tartrate-carbonate reagent (alkaline copper solution), Folin-Ciocalteu phenol reagent (2 N), BSA protein standard (2 mg/mL in 0.9% NaCl with 0.05% NaN₃), sodium deoxycholate (DOC, 0.15%), trichloroacetic acid (TCA, 72%), SDS solution (5%), detailed protocol |
| Storage Conditions | 15-25 °C; Folin reagent protect from light (light-sensitive); BSA standard at 4 °C |
| Shelf Life | 12 months from manufacture date; Folin reagent may develop precipitate — do not use if heavy precipitate persists after warming |
| Package Specifications | 500 assays (standard), 2,000 assays (micro); 96-well plate compatible format available |
| Product Form | Liquid reagents; BSA standard liquid |
| Key Features | Modified Lowry (Peterson's) includes DOC-TCA precipitation for interferent removal; higher sensitivity than Bradford; less protein variation than Coomassie; SDS-compatible after precipitation; classical method validated by decades of literature; 96-well microplate adaptable |
| Purity | Folin-Ciocalteu reagent 2 N ± 0.1 N; BSA standard >98% by electrophoresis, fatty acid-free; copper reagent meets ACS specifications |
| Concentration | As specified on product label or certificate of analysis |
| Activity / Unit Definition | Binding capacity or enzymatic activity as specified per product documentation |
| Molecular Weight | Varies by product as specified in documentation |
| Source / Origin | Recombinant expression in E. coli, mammalian, or insect cell systems; synthetic chemistry for small molecule reagents |
| pH Range / Optimal pH | pH 7.0–8.0 for most protein applications |
| Shipping Conditions | Ambient; Folin reagent corrosive — ship per Class 8; BSA standard cold pack |
| Expiration Date / Stability | 12 months at 15-25 °C; Folin reagent: if yellowish-green crystals form, warm to 37 °C and shake — if they do not dissolve, discard; BSA standard 12 months at 4 °C; do not freeze BSA standard |
| Regulatory / Compliance | For laboratory and research use only; RUO; Folin-Ciocalteu reagent contains phosphoric acid and tungsten compounds — corrosive; TCA is corrosive; ISO 9001 |
| Compatibility | Compatible with standard SDS-PAGE, Western blot, mass spectrometry, and chromatography systems |
| Recommended Buffer System | PBS, Tris, or HEPES buffers as specified in product protocol |
| Application Notes / Precautions | Avoid repeated freeze-thaw cycles for protein solutions; use fresh aliquots; protect light-sensitive reagents |
| Batch-to-Batch Consistency | Protein concentration and activity within ±15% of reference lot |
For research use only, not for clinical use.
|
There is no product in your cart. |
Copyright © 2026 Alta DiagnoTech. All rights reserved.
