Thermo Scientific™

Pierce™ Quantitative Colorimetric Peptide Assay

Catalog number:  23275

Related applications:

Protein Assays and Analysis

| Protein Mass Spectrometry Analysis

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The Thermo Scientific™ Pierce™ Quantitative Colorimetric Peptide Assay is an easy-to-use colorimetric microplate assay designed specifically to improve the sensitivity and reproducibility of quantitation of peptide mixtures.

Sensitive—accurately detect as little as 25 µg/mL of peptide mixture
Robust—assay performance rigorously tested using peptide digest mixtures
Robust peptide digest standard—kit includes a validated peptide digest standard for improved reproducibility of quantitation
Compatible—works with many reagents, including mass spectrometry sample preparation reagents and TMT™-labeled peptides
Convenient—easy mix-and read-format and stable colorimetric signal that may be read in as little as 15 minutes

The Pierce Quantitative Colorimetric Peptide Assay provides modified BCA reagents for the reduction of Cu+2 to Cu+1 and a proprietary chelator that have been optimized for the quantitation of peptide mixtures. In this reaction, the copper is first reduced by the amide backbone of peptides under alkaline conditions (Biuret reaction). The proprietary chelator then couples with the reduced copper to form a bright red complex with absorbance of 480 nm. The signal produced from this reaction is 3-4 fold more sensitive than the Micro-BCA Protein Assay for peptide analysis.

The kit also contains a high quality peptide digest reference standard for use in generating linear standard curves and to serve as a calibration control. This colorimetric peptide assay requires a small amount of sample (20 µL) and has a working peptide concentration range of 25–1000 μg/mL. The increased sensitivity, low sample assay volume, and included reference standard are essential for accurate and robust measurement of peptide digest samples, especially for mass spectrometry applications.

• Recommended for peptide mixtures
• Not recommended for synthetic peptides because the assay is affected by peptide amino acid content
• Normalizing sample concentrations for quantitative downstream applications
• Normalizing sample loading volumes for LC, MS, and LC/MS applications
• Measuring recovery after peptide clean-up procedures
For Research Use Only. Not for use in diagnostic procedures.


Product Line: Pierce™
Workflow Step: In-Process Testing
Detection Method: Colorimetric
Final Product Type: Peptide
For Use With (Equipment): Microplate Reader
Starting Material: Peptides, Protease-digested protein

Contents & storage

Colorimettric Assay Reagent A, 50 mL
Colorimetric Assay Reagent B, 2 x 25 mL
Colorimetric Assay Reagent C, 2 mL
Peptide Digest Assay Standard, 1.5 mL

Store in refrigerator (2–8°C).