3,3’-Dithiobis[6-nitrobenzoic Acid]

• CAT Number: R016632
• CAS Number: 69-78-3
• Molecular Formula: C₁₄H₈N₂O₈S₂
• Molecular Weight: 396.35
• Purity: ≥95%
• Synonyms: 2,2’-Dinitro-5,5’-dithiodibenzoic Acid; 3,3’-Dithiobis(6-nitrobenzoic Acid); 5,5’-Dithiobis[2-nitrobenzoic Acid]; Ba 2767; DTNB; Ellman’s Reagent
• Storage: Room temperature
• IUPAC Name: 5-[(3-carboxy-4-nitrophenyl)disulfanyl]-2-nitrobenzoic acid
• InChI: InChI=1S/C14H8N2O8S2/c17-13(18)9-5-7(1-3-11(9)15(21)22)25-26-8-2-4-12(16(23)24)10(6-8)14(19)20/h1-6H,(H,17,18)(H,19,20)
• InChIKey: KIUMMUBSPKGMOY-UHFFFAOYSA-N
• SMILES: C1=CC(=C(C=C1SSC2=CC(=C(C=C2)[N+](=O)[O-])C(=O)O)C(=O)O)[N+](=O)[O-]

3,3’-Dithiobis[6-nitrobenzoic acid] (Cat No.:R016632), also known as Ellman’s reagent, is a colorimetric compound widely used to quantify free thiol groups in proteins and other biological samples. Upon reaction with sulfhydryl groups, DTNB releases 2-nitro-5-thiobenzoate (TNB), producing a yellow color measurable at 412 nm. This sensitive and reliable reagent is essential in enzymology, protein folding studies, and redox biology. DTNB is water-soluble, stable under standard conditions, and suitable for both endpoint and kinetic assays, making it a valuable tool in biochemical and pharmaceutical research.