Eosin Y, xanthene dye(AB146325)

MW 647.9 g/mol. A red fluorescent dye from the xanthene family used as an acidic red stain for cell cytoplasm. Reduces the affinity of Mg2+-ATPase for ATP and increases the enzyme affinity for Mg2+ at concentrations of 10-50 μM. At higher concentrations near 100 μM the affinity for Mg2+-ATPase for the ion-activator has been shown to be reduced.