Fluorescent indicator dyes for calcium working at long wavelengths.

摘要

A new class of calcium specific fluorescent indicator dyes having visible excitation and emission wavelengths combine at least one tricyclic chromophore with a tetracarboxylate parent CA<2><+> chelating compound having the octacoordinate pattern of liganding groups characteristic of BAPTA to give a rhodamine-like or fluorescein-like fluorophore. Binding of calcium<2><+> increases the fluorescence of the new compounds by up to 40-fold. The calcium<2><+> dissociation constants are in the range 0.37-2.3 microM, so that the new indicators give better resolution of high [CA<2><+>] levels than were previously obtainable with predecessor compounds such as quin-2 or fluo-2. The visible excitation wavelengths of the new compounds are more convenient for fluorescent microscopy and flow cytometry than the UV required by previous indicators.