Quin 2 forms a stable fluorescent complex with calcium (logKCaY=7.1), but not with magnesium (logMgY=2.7). The complex has a high quantum yield (0.14) at emission wavelength 525 nm, excitation wavelength 339 nm, and emission wavelength 492 nm. Quin 2-AM is an acetoxymethyl ester derivative of Quin 2 that is readily permeable through cell membranes. Within the cell, the ester is hydrolyzed to Quin 2.
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