> In response to the posting by Chris Frederickson, we have recently > developed several new cytosolic zinc indicators that have reasonably > high affinity, some of which are ratioable and potentially useful in > both imaging and flow cytometry. > > I don't mean to be commercial but here is the applicable text from my > Handbook, which has just recently been revised. You will have to go to > this link to get the figures. > > http://www.probes.com/handbook/sections/2007.html > > FuraZin-1, FluoZin-1 and Related Indicators > > Zinc concentrations in the 1–100 nM range can be measured using > fluorescent indicators nominally designed for Ca2+ detection such as > fura-2 (see > below), or more recently developed indicators with greater Zn2+ > selectivity. We have focused our development efforts on probes for > detection > of higher Zn2+ concentrations that are present in synaptic vesicles > and released in response to electrical stimulation or excitotoxic > agonists. > Peak concentrations of synaptically released Zn2+ may exceed 100 µM. > We are pleased to introduce FuraZin-1 (F-24182, F-24183), IndoZin-1 > (I-24184, I-24185), FluoZin-1 (F-24180, F-24181), FluoZin-2 (F-24188, > F-24189) and RhodZin-1 (R-24186, R-24187), a new series of indicators > designed for detection of Zn2+ in the 0.1–100 µM range with minimal > interfering Ca2+ sensitivity (panels H and N, Figure 20.32). FuraZin-1 > and > IndoZin-1 exhibit Zn2+-dependent excitation and emission spectral > shifts, respectively; FluoZin-2 (Figure 20.28) and RhodZin-1 (Figure > 20.29) show > Zn2+-dependent fluorescence without accompanying spectral shifts. > > FluoZin-3 Indicator > > FluoZin-3 is a new Zn2+-selective indicator derived from the Ca2+ > indicator fluo-4 by addition of a methoxy substituent to the BAPTA > chelator. > FluoZin-3 (F-24194) exhibits moderately high Zn2+-binding affinity > (Kd(Zn2+) ~350 nM (Figure 20.27) that is unperturbed by Ca2+ > concentrations > up to at least 1 µM. The Zn2+-specificity of FluoZin-3 evident from > measurements in calibration solutions is reproduced in cell-based > experiments. > Molecular Probes' researchers have found that in HeLa cells loaded > with the cell-permeant AM ester form of FluoZin-3 (F-24195), addition > of 1 µM > Ca2+ in the presence of ionomycin produces no detectable response > whereas subsequent addition of 10 nM Zn2+ in the presence of > pyrithione > (P-24193, Section 20.8) results in a large fluorescence increase. >
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