Fluorescent calcium imaging agent; structurally related to BAPTA, q.v. Ca2+ binding causes a spectral shift to shorter wavelengths; ratio of the fluorescence at each wavelength is related to changes in Ca2+ binding and is independent of dye concentration. Also used as pentaacetoxymethyl ester, Fura-2/AM, to enhance crossing of membranes. Prepn: G. Grynkiewicz et al., J. Biol. Chem. 260, 3440 (1985). Binding kinetics to Ca2+: A. P. Jackson et al., FEBS Lett. 216, 35 (1987). Determn of Kd: D. L. Groden et al., Cell Calcium 12, 279 (1991). Spectra of intracellular forms: C. S. Owen, ibid. 385. Photophysics: V. Van den Bergh et al., Biophys. J. 68, 1110 (1995). HPLC determn: M. Castle, E. Neuteboom, J. Chromatogr. A 696, 93 (1995). Determn in tissue: N. N. P. Tran et al., Cell Calcium 18, 420 (1995). Practical aspects of use in intracellular Ca2+ measurement: K. R. Sipido, G. Callewaert, Cardiovasc. Res. 29, 717 (1995).