Water soluble and stable nitric oxide radical scavenger that shows in chemical and biological systems antagonistic action against the free nitric oxide radical (NO·). The inhibitory effects were almost 2-fold stronger than those of NMMA (ALX-106-001) and NOARG (ALX-105-001). Reacts with nitric oxide in a stoichometric manner. Can be used for an improved detection of nitric oxide in activated macrophage cultures in combination with the Griess reagent (ALX-400-004). Protects against endotoxin shock. Alternative name: 2-(4-Carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide . potassium salt. Purity: ≥99% (HPLC). Solubility: Soluble in 100% ethanol, methanol, DMSO or dimethyl formamide. Highly soluble in water or aqueous buffers, e. g. PBS, pH 7.2. Long Term Storage: -20°C.