Amplex Red

Amplex Red (CAS No.: 119171-73-2) is a fluorogenic probe widely used in biochemical and cell-based assays for the sensitive detection of hydrogen peroxide and peroxidase activity. As a non-fluorescent derivative of resorufin, it serves as a stable substrate for horseradish peroxidase (HRP), undergoing oxidation in the presence of hydrogen peroxide to generate the highly fluorescent product resorufin, enabling quantitative fluorescence-based readouts with excitation and emission maxima in the approximate ranges of 520–550 nm and 585–595 nm. This reaction underpins its utility in monitoring oxidative stress, redox signaling, and enzymatic activity of oxidases, including NADPH oxidases, in diverse biological systems. Amplex Red is commonly employed in studies of reactive oxygen species production, mitochondrial function, and immune cell activation, as well as in high-throughput screening assays for compounds that modulate oxidative pathways. Its high sensitivity allows detection of hydrogen peroxide at low micromolar to nanomolar levels under optimized assay conditions, although experimental concentrations and assay configurations vary depending on the biological context and detection platform.