DAX-J2™ Ratio 580/460, a Ratiometric Nitric Oxide (NO) Probe

DAX-J2™ Ratio 580/460 is a new nitric oxide (NO) sensor recently developed by AAT Bioquest. It is a cell permeable reagent that can measure free NO and nitric oxide synthase (NOS) activity in living cells in a ratiometric mode. Once inside the cell the blocking groups on the DAX-J2™ reagent are released to induce fluorescence ratio changes at wavelengths of 580 and 460 nm upon NO oxidation. The fluorescence intensities at 580 nm and 460 nm can be detected using the filter sets of Cy3^®/TRITC and BD Horizon™ V450/ Pacific Blue. Most of flow cytometers and fluorescence microscopes are equipped with these two filter sets. DAX-J2™ Ratio 580/460 has distinct advantages for NO detection over the popular DAF-2 NO probe:

1. DAX-J2™ Ratio 580/460 does not require esterase activity for NO detection. DAF-2 requires intracellular esterases to cleave its acetate groups for detecting NO activity.
2. DAX-J2™ product exhibits pH-independent fluorescence while DAF-2 has its fluorescence highly affected by pH.
3. DAX-J2™ Ratio 580/460 can be monitored in a ratiometric mode.