C18H24N6O6S4
M.W. 548.68
Appearance: Light yellow-green to green powder
Solubility: 50mg/mL in H2O,clear to very slightly haze, light yellow-green to green
Purity: ≥98.0%

ABTS has been used as a chromogenic substrate for horseradish peroxidase (HRP), both in general activity assays and in ELISA applications. Activity of HRP using ABTS appears about four-fold higher than using pyrogallol.

The peroxidase-catalyzed reduction of hydrogen peroxide to water is coupled to a one-electron oxidation of ABTS, forming a metastable radical cation. This cation gives a brilliant blue-green solution,lmax = 414 nm and additional peaks at 395, 640 and 725 nm. Reduced ABTS has a characteristic peak at 340 nm; the isosbestic point is approximately 375 nm.