Ellman's reagent, also known as 5,5'-Dithio-bis(2-nitrobenzoic acid) or DTNB, is a chemical reagent used to quantify the number or concentration of thiol groups in a sample. It is particularly useful in biochemistry and molecular biology for the detection of free sulfhydryl groups in proteins, peptides, and other small molecules. In histology, Ellman's reagent is utilized to stain and identify specific cellular components that contain thiol groups.
