Table 19.5 Response of fura-2 and indo-1 to some divalent cations other than Ca2+ and Mg2+.

Ion Indicator Kd * Spectroscopic Effect Reference
Ba2+ fura-2 1.4 × 10-6 M Spectra similar to Ca2+ complex; no quenching ref
Cd2+ fura-2 1.0 × 10-12 M Spectra similar to Ca2+ complex; higher intensity ref
Co2+ fura-2 8.6 × 10-9 M >99% Quenched relative to Ca2+ complex ref
Mn2+ fura-2 2.8 × 10-9 M >99% Quenched relative to Ca2+ complex ref
Pb2+ fura-2 4.2 × 10-12 M Spectra shifted relative to Ca2+ complex; no quenching ref
Pb2+ indo-1 3.5 × 10-11 M Fluorescence quenched ref
Sr2+ fura-2 7.6 × 10-6 M Spectra similar to Ca2+ complex; no quenching ref
Zn2+ fura-2 3.0 × 10-9 M Spectra similar to Ca2+ complex; no quenching ref
Zn2+ indo-1 1.6 × 10-10 M Spectra similar to Ca2+ complex; no quenching ref
* Dissociation constant reported in cited literature reference.