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 mol⁻ 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. TMBHK, available from BioVision Inc., is a highly sensitive single component reagent that is ready to use for the quantitative detection of HRP bound to a solid phase or in free solution. TMBHK is stable at room temperature for six months and is 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 commonly employed in immunologic assays.

Additional Information

Synonyms	3,3',5,5'-Tetramethylbenzidine; TMBHK
Product #	T-2463
CAS #	54827-17-7
Chemical Name	3,3',5,5'-Tetramethylbenzidine; TMBHK
Formula	C16H20N2
MW	240.35
Appearance	Liquid
Storage Temp	+4°C
Use	TMB is a chromogenic substrate used in staining procedures in immunohistochemistry as well as being a visualising reagent used in enzyme-linked immunosorbent assays

Additional Information

MDL Number	MFCD00007748
ChemACX	X1009100-2
InChI	InChI=1S/C16H20N2/c1-9-5-13(6-10(2)15(9)17)14-7-11(3)16(18)12(4)8-14/h5-8H,17-18H2,1-4H3
SMILES	Cc1cc(cc(c1N)C)c2cc(c(c(c2)C)N)C