– Fura-2, pentaammonium salt is a ratiometric fluorescent dye that binds to free intracellular calcium. It is membrane-impermeant and may be loaded into cells via microinjection or scrape loading.    A major use of Fura-2 is in drug discovery, for measuring intracellular calcium mobilization after activation of G protein-coupled receptors (GPCRs) and calcium channels. Upon calcium binding, the fluorescent excitation maximum of the indicator undergoes a blue shift from 363 nm (Ca²-free) to 335 nm (Ca²-saturated), while the fluorescence emission maximum is relatively unchanged at ~510 nm. 

 
• Light yellow solid soluble in DMSO
 
• Store at 4°C and protect from light, especially in solution
 
• K_d: 145 nM (22°C in pH 7.2 buffer)
 
• &lamba; _Ex/&lamba;_Em (no Ca²) = 363/512 nm; &lamba; _Ex/&lamba; _Em (high Ca²) = 335/505 nm
 
• ε (363 nm, no Ca²) = 27,000 M^-1cm^-1; ε (335 nm, high Ca²) = 35,000 M^-1cm^-1
 
• C₂₉H₃₇N₈O₁₄
 
• MW: 721
 

Handling

Store with desiccant; Protect from light