4-Methylumbelliferyl phosphate disodium salt

White to off-white powder. Soluble in water (50 mg/ml). Chemical. CAS: 22919-26-2. Formula: C10H7Na2O6P. MW: 300.11. 4-Methylumbelliferyl phosphate (4-MUP) is a fluorogenic substrate for phosphatases (mainly alkaline). It is converted to the fluorescent product 4-methylumbelliferone (4-MU), which has an emission maximum at 445-454 nm. The excitation maximum for 4-MU is pH-dependent: 330, 370, and 385 nm at pH 4.6, 7.4, and 10.4, respectively. Therefore, this phosphatase substrate is not well suited for living cell or continuous assays since 4-MU only develops maximum fluorescence at a pH value of >10. Spectral data: lambdaex=319nm, lambdaem=384nm (pH 9.0). lambdaex=360nm, lambdaem=449nm (for reaction product).