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Furaptra (Mag-Fura-2), Tetrapotassium Salt

Mag-Fura-2 is a UV-excitable fluorescent indicator for magnesium with a Kd of 1.9 mM (1,2).

Product Attributes

CAS number



Calcium indicators

Cell permeability

Membrane impermeant

Indicator type




Catalog #
1 mg
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Product Description

Mag-Fura-2 is a UV-excitable fluorescent indicator for magnesium with a Kd of 1.9 mM (1,2). Similar to Fura-2, the excitation wavelength of Mag-Fura-2 undergoes a blue shift from 369 nm to 330 nm. Mag-Fura-2 also responds to Ca2+ but with a significantly lower Kd than Fura-2 for Ca2+. An important application of Mag-Fura-2 is its use in detecting high, transient Ca2+ concentration during Ca2+ spikes (3,4). Mag-Fura-2/tetraammonium salt can be loaded into cells by microinjection or scrape loading. Also see Mag-Fura-2, tetrasodium salt (50036) and the cell membrane-permeant Mag-Fura-2 AM ester (50037, 50038, 50039).

  • Light yellow solid soluble in water (pH > 6)
  • Store at -20°C and protect from light
  • C18H10K4N2O11
  • MW: 587
  • [132319-57-4]



1. PNAS 86, 2981 (1989).

2. Am J Physiol 256, C540 (1989).

3. Neuron 10, 21 (1993).

4. Biophys J 68, 2156 (1995).


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