Mag-Fura-2 is a UV-excitable fluorescent indicator for magnesium with a Kd of 1.9 mM. Similar to Fura-2, the excitation wavelength of Mag-Fura-2 undergoes a blue shift from 369 nm to 330 nm. Mag-Fura-2 also responds to Ca2 but with a significantly lower Kd than Fura-2 for Ca2 . An important application of Mag-Fura-2 is its use in detecting high, transient Ca2 concentration during Ca2 spikes. Mag-Fura-2/tetrasodium salt can be loaded into cells by microinjection or scrape loading. Also see Mag-Fura-2, tetrapotassium salt and the cell membrane-permeant Mag-Fura-2 AM ester.    Light yellow solid soluble in water (pH > 6)  Store at 4°C and protect from light  C18H10N2Na4O11  MW: 523