A sensitive substrate for the detection of horseradish peroxidase activity. Absorbs at 450 nm (yellow end-product). Ideal for ELISA and solution assays. Soluble. Reaction Condition: 80 µg/ml in 1 M Sodium Acetate and 0.01% H2O2, pH 5.8. Stop with 1 M H2SO4. Absorbs at 450 nm.