73630-23-6

Quin-2 is a high-affinity fluorescent calcium indicator (K_d = 115 nM for calcium). 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/emission maxima for quin-2 are 339 and 492 nm, respectively.

2-[(2-amino-5-methylphenoxy)methyl]-6-methoxy-8-aminoquinoline-n,n,n',n'-tetraacetic acid tetrapotassium salt can be used as a fluorescent highly selective Ca2+ indicator exhibiting fast uptake and release of Ca2+. Used as a calibration substance in the measurement of cytoplasmic free calcium.

QUIN 2, Tetrapotassium Salt is a useful fluorescing calcium indicator. It can also be used in biological study of practical aspects of measuring intracellular calcium signals with fluorescent indicators.

Binding of Ca²⁺ to QUIN 2 leads to a major shift in UV absorption spectrum and a twenty-fold enhancement in fluorescence quantum yield. TPEN (Cat. No. 616394) can be used in conjunction with QUIN 2 to reduce heavy-metal quenching of QUIN 2 fluorescence in cells. Spectral properties in the presence of low calcium concentrations (ex. 354 nm, em. 510 nm) differ from those during high calcium conditions (ex. 332 nm, em. 505 nm).

Primary TargetCalcium Probes

339 nm/492 nm