DTNB is an acronym that stands for 5,5'-dithiobis-(2-nitrobenzoic acid), an organic compound commonly used in biochemical and scientific research. It is primarily utilized as a reagent for detecting and quantifying sulfhydryl groups in proteins and other biomolecules.
DTNB has a yellow color and forms a chromophore when it reacts with sulfhydryl compounds, resulting in the production of a yellow product that can be measured spectrophotometrically. This reaction is known as the Ellman's assay, named after the scientist who first described this methodology.
In the Ellman's assay, DTNB reacts with the sulfhydryl groups (-SH) present in molecules such as cysteine residues of proteins, coenzymes, or glutathione. This reaction forms a disulfide bond between DTNB and the sulfhydryl group, generating a compound called 2-nitro-5-thiobenzoate, which is yellow in color.
By measuring the absorbance of the yellow product at a specific wavelength, scientists can determine the concentration of sulfhydryl compounds in a sample. This technique is widely employed in various fields, including biochemistry, enzymology, and pharmaceutical research, to assess the redox status, determine enzyme activity, or evaluate changes in protein structure caused by oxidative stress.
DTNB has become an essential tool in scientific investigations to understand the role of sulfhydryl groups and gain insights into numerous biological processes related to protein folding, disulfide bond formation, and enzymatic reactions.
