3,3'5,5'-Tetramethylbenzidine (TMB) has been shown to be a safe-sensitive substrate for the assay of horseradish peroxidase (HRP). Initially, in the presence of HRP and hydrogen peroxide, a one-electron oxidation product is formed. This compound, a cation free radical, is blue in color with an adsorption maximum at 653 nm. Further reaction with HRP/H, or acidification of the radical with acid yields the diimine terminal oxidation product adsorbing light at 450 nm. The extinction coefficient of the radical (E653 nm = 3.9 x 10 mo⁻1 cm⁻) and diimine (E450 nm = 5.9 x 10 mol⁻ cm⁻) provide a remarkably sensitive system for the assay of HRP and HRP labeled probes. TMBUS, available from Biovision Inc., is a single component reagent stable at room temperature and not sensitive to normal laboratory light. It is optimized with respect to TMB and hydrogen peroxide concentrations and yields a linear response with the concentrations of HRP usually employed in immunologic assays.
TMB is a chromogenic substrate used in staining procedures in immunohistochemistry as well as being a visualising reagent used in enzyme-linked immunosorbent assays
Protect from light
|Handling||Protect from light|
|UN #'S||Not Applicable|
|Packing Group||Not Applicable|