Apollo Sci. 5,5'-Dithiobis(2-nitrobenzoic acid) (Ellmans reagent, DTNB)

5,5'-Dithiobis(2-nitrobenzoic acid), widely known as DTNB or Ellman’s Reagent, is a colorimetric reagent used for the quantification of free sulfhydryl (–SH) groups in biomolecules. Upon reaction with thiol-containing compounds, DTNB releases 2-nitro-5-thiobenzoate (TNB), a chromogenic product that absorbs strongly at 412 nm, allowing sensitive spectrophotometric detection.

This Apollo Scientific grade reagent, supplied in various quantities and in bottle-packaged solid form, is well-suited for biochemical, enzymatic, and protein modification assays. Its stability and specificity make it a trusted tool in protein chemistry and enzymology.

Key Features

• High-performance thiol-detecting reagent
• Produces yellow-colored TNB upon reaction with thiols
• Absorbance peak at 412 nm for spectrophotometric quantification
• Suitable for enzyme activity and protein structure analysis
• Stable under ambient storage conditions
• Classified as an irritant – appropriate PPE required

Applications

• Quantitative analysis of free sulfhydryl groups in proteins and peptides
• Enzyme kinetics assays (e.g., glutathione reductase)
• Evaluation of glutathione levels in biological samples
• Thiol-disulfide exchange reaction studies
• Structural and functional analysis in protein chemistry
• Commonly used in colorimetric assays in life sciences and diagnostics

Chemical & Physical Properties

Available Packaging

Apollo Scientific™ DTNB (Ellman’s Reagent) offers researchers a high-purity, reliable tool for thiol detection and enzyme activity assays. Its clear reaction endpoint and strong absorbance at 412 nm make it indispensable in protein biochemistry, oxidative stress analysis, and redox research workflows.