Fluo-3FF (potassium salt)

Fluo-3FF is a fluorescent calcium indicator. It is a di-fluorinated analog of Fluo-3 that displays about a 100-fold lower affinity than Fluo-3 for calcium (Kds = 42 and 0.4 ?M, respectively) . 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. Fluo-3FF has excitation/emission maxima of approximately 506 and 526 nm, respectively.