ABSTRACT
Over the past decade, fluorescence-based determinations of free metal ions in solution using variants of human apocarbonic anhydrase (apoCA) have been demonstrated to be highly sensitive, selective, and versatile. In particular, free divalent copper, zinc, cobalt, cadmium, and nickel have been determined at concentrations down to the picomolar range
by changes in fluorescence emission
and excitation wavelength ratios,
lifetimes,
and anisotropy (polarization).
