10-Acetyl-3,7-dihydroxyphenoxazine (N-Acetyl-3,7-dihydroxyphenoxazine or ADHP), which has been marketed under the name Amplex® Red, is regarded as the best fluorogenic substrate for peroxidase because it is highly specific and stable. The substrate itself is nearly colorless and nonfluorescent until it is oxidized by H2O2(reacting in a 1:1 stoichiometry) in the presence of horseradish peroxidase (HRP) to become the highly red fluorescent resorufin. H2O2 is produced by many enzymatic reactions, and thereforeADHP can be used to detect the activity of many different enzymes. Detect HRP in immunoassays Detect trace amounts of hydrogen peroxide (H2O2) Detect using fluorometer or microplate reader λEx/λEm(pH 9)= 571/585 nm (end product) ε= 54,000 (end product) White to off-white solid soluble in DMSO or DMF Store desiccated at -20°C and protect from light C14H11CNO4 MW: 257.24 [119171-73-2]Amplex Red is a registered trademark of Thermo Fisher Scientific.