Quin-2 AM is a cell-permeant acetoxymethyl ester of the high affinity fluorescent calcium indicator quin-2 . As quin-2 AM enters cells, it is hydrolyzed by intracellular esterases to produce quin-2. Quin-2 binds calcium with a Kd value of 115 nM. It displays high selectivity for calcium, as it is not affected by sodium gradients, membrane potential, or intracellular pH. High affinity probes like quin-2 are ideal for monitoring low levels of calcium, as are found in resting cells. Loadings of up to 2 mM quin-2 are without serious toxic effects, so quin-2 may be used to buffer intracellular calcium transients. Excitation and emission maxima for quin-2 are 339 and 492 nm, respectively.
Fluorescent probe for measurement of calcium in biological systems and for selected divalent cations.
2-[(2-Amino-5-methylphenoxy)methyl]-6-methoxy-8-aminoquinoline-N,N,N',N'-tetraacetic acid tetrakis(acetoxymethyl ester)
Quin 2-AM is a cell permeable fluorescent probe for Ca2+ that gives a large shift in the UV absorption spectrum and a 20-fold increase in fluorescence upon Ca2+ binding.
