Rhod-5NAM is a cell-permeant acetoxymethyl ester of the fluorescent calcium indicator rhod-5N . As rhod-5NAM enters cells, it is hydrolyzed by intracellular esterases to produce rhod-5N. Rhod-5N displays a low affinity for calcium (Kd = 19 μM). Low affinity calcium indicators are particularly useful for studying compartments with high concentrations of calcium, such as endoplasmic reticulum, where high affinity dyes will be insensitive to luminal fluctuations. Rhod-5N has excitation emission maxima of approximately 551 and 576 nm, respectively.