FURA-FF, AM

Description

Fura-FF AM is a cell-permeable acetoxymethyl ester of the fluorescence calcium indicator fura-FF (potassium salt) . As fura-FF AM enters cells, it is hydrolyzed by intracellular esterases to produce fura-FF. Fura-FF is a difluorinated derivative of the calcium indicator fura-2 . Unlike, fura-2, fura-FF has negligible magnesium sensitivity, thus reducing interference from this cation.¹ Fura-FF also has a higher calcium dissociation constant than fura-2 (K_d(calcium) = 6 and 0.14 μM, respectively).^1,2 However, the spectral properties of fura-FF and fura-2 are similar with fura-FF displaying excitation/emission spectra of 365/514 nm in the absence of calcium, with a shift to 339/507 nm in the presence of a high calcium concentration.³ Low affinity calcium dyes, including fura-FF, are preferred for studying compartments with high concentrations of calcium, such as mitochondria, or in cell systems that have relatively low calcium buffering capacities, such as neuronal dendrites and spines.^4,5,6

References

1. Hyrc, K.L., Bownik, J.M., and Goldberg, M.P. Ionic selectivity of low-affinity ratiometric calcium indicators: mag-Fura-2, Fura-2FF and BTC Cell Calcium 27(2),75-86(2000).
2. Grynkiewicz, G., Poenie, M., and Tsien, R.Y. A new generation of Ca²⁺ indicators with greatly improved fluorescence properties J. Biol. Chem. 260(6),3440-3450(1985).
3. Ruggiu, A.A., Bannwarth, M., and Johnsson, K. Fura-2FF-based calcium indicator for protein labeling Org. Biomol. Chem. 8(15),3398-3401(2010).
4. Aponte, Y., Bischofberger, J., and Jonas, P. Efficient Ca²⁺ buffering in fast-spiking basket cells of rat hippocampus J. Physiol. 586(8),2061-2075(2008).
5. Canepari, M., Vogt, K., and Zecevic, D. Combining voltage and calcium imaging from neuronal dendrites Cell. Mol. Neurobiol. 28(8),1079-1093(2008).
6. Marcu, R., Neely, C.K., Karamanlidis, G., et al. Multi-parameter measurement of the permeability transition pore opening in isolated mouse heart mitochondria J. Vis. Exp. 67:4131,(2012).