Our Amplite(TM) Red is a sensitive fluorogenic peroxidase substrate that generates a highly red fluorescent product that has maximum absorption of 571 nm and maximum emission of 585 nm. Unlike other HRP substrates such as dihydrofluoresceins and dihydrorhodamines, the air-oxidation of Amplite(TM) Red is minimal. Amplite(TM) Red is one of the most sensitive and stable fluorogenic probes for detecting HRP and H2O2. Amplite(TM) Red has been widely used to detect HRP in many immunoassays. On the other hand, Amplite(TM) Red can also be used to detect trace amount of H2O2. The Amplite(TM) Red-based H2O2 detection is at least one order of magnitude more sensitive than the commonly used scopoletin assay for H2O2. Because H2O2 is produced in many enzymatic redox reactions, Amplite(TM) Red can be used in coupled enzymatic reactions to detect the activity of many oxidases and/or related enzymes/substrates or cofactors such as glucose, acetylcholine and cholesterol, L-glutamate, amino acids, etc.