Thermo Scientific™ 5,5'-Dithiobis(2-nitrobenzoic acid) (Ellmans reagent, DTNB) ≥99%

5,5'-Dithiobis(2-nitrobenzoic acid), commonly known as Ellman’s Reagent or DTNB, is a widely used compound in biochemistry and molecular biology for the quantitative determination of free sulfhydryl (–SH) groups in proteins and peptides. It reacts with thiol groups to form a mixed disulfide and releases 2-nitro-5-thiobenzoate (TNB), a yellow-colored product with a characteristic absorbance at 412 nm, making it ideal for spectrophotometric analysis.

Supplied at ≥99% purity, this reagent appears as a yellow crystalline powder and is stable under ambient conditions. It is a gold standard reagent for thiol quantification, enzyme activity assays, and protein modification studies.

Key Features

• High purity: ≥99%
• Spectrophotometric detection at λ = 412 nm
• Sensitive and specific for thiol group quantification
• Compatible with a wide range of biological buffers
• Ideal for use in protein, enzyme, and peptide analysis
• Stable yellow powder for long-term storage
• GHS07 irritant classification – handle with PPE

Applications

• Quantification of free sulfhydryl groups in biomolecules
• Enzyme kinetics and activity studies (e.g. glutathione reductase assays)
• Detection of thiol-disulfide exchange reactions
• Protein structure and stability investigations
• Monitoring of glutathione (GSH) levels
• Used in colorimetric assays for thiol estimation in plasma, tissues, and cell extracts

Chemical & Physical Properties

Available Packaging

Thermo Scientific™ DTNB (Ellman’s Reagent), ≥99% is an essential reagent for quantitative analysis of thiol groups in proteins, enzymes, and other biomolecules. With high purity and excellent stability, it is a reliable tool for researchers in biochemistry, enzymology, and molecular diagnostics, offering sensitive and reproducible results via simple spectrophotometric measurement.