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Cal-590™, potassium salt

Fluorescence emission spectra of Cal-590&trade; in solution containing 0 to 39 &micro;M free Ca<sup>2+</sup>.
Fluorescence emission spectra of Cal-590&trade; in solution containing 0 to 39 &micro;M free Ca<sup>2+</sup>.
Fluorescence emission spectra of Cal-590&trade; in solution containing 0 to 39 &micro;M free Ca<sup>2+</sup>.
Ca2+ Dependent Dose Response of Cal-590.
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Physical properties
Dissociation constant (Kd, nM)561
Molecular weight1123.03
Spectral properties
Extinction coefficient (cm -1 M -1)78000
Excitation (nm)574
Emission (nm)588
Quantum yield0.621
Storage, safety and handling
H-phraseH303, H313, H333
Hazard symbolXN
Intended useResearch Use Only (RUO)
R-phraseR20, R21, R22
StorageFreeze (< -15 °C); Minimize light exposure
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Molecular weight
Dissociation constant (Kd, nM)
Extinction coefficient (cm -1 M -1)
Excitation (nm)
Emission (nm)
Quantum yield
Calcium measurement is critical for numerous biological investigations. Fluorescent probes that show spectral responses upon binding calcium have enabled researchers to investigate changes in intracellular free calcium concentrations by using fluorescence microscopy, flow cytometry, fluorescence spectroscopy and fluorescence microplate readers. Rhod-2 is most commonly used among the red fluorescent calcium indicators. However, Rhod-2 AM is only moderately fluorescent in live cells upon esterase hydrolysis, and has very small cellular calcium responses. Cal-590™ has been developed to improve Rhod-2 cell loading and calcium response while maintaining the spectral wavelength of Rhod-2, making it compatible with TRITC/Cy3® filter set. In CHO and HEK cells Cal-590™ AM has cellular calcium response that is much more sensitive than Rhod-2 AM. The spectra of Cal-590 is well separated from those of FITC, Alexa Fluor® 488 and GFP, making it an ideal calcium probe for multiplexing intracellular assays with GFP cell lines or FITC/Alexa Fluor® 488 labeled antibodies.


Common stock solution preparation

Table 1. Volume of Water needed to reconstitute specific mass of Cal-590™, potassium salt to given concentration. Note that volume is only for preparing stock solution. Refer to sample experimental protocol for appropriate experimental/physiological buffers.

0.1 mg0.5 mg1 mg5 mg10 mg
1 mM89.045 µL445.224 µL890.448 µL4.452 mL8.904 mL
5 mM17.809 µL89.045 µL178.09 µL890.448 µL1.781 mL
10 mM8.904 µL44.522 µL89.045 µL445.224 µL890.448 µL

Molarity calculator

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Spectral properties

Extinction coefficient (cm -1 M -1)78000
Excitation (nm)574
Emission (nm)588
Quantum yield0.621



View all 8 citations: Citation Explorer
Development of a deep two-photon calcium imaging method for the analysis of cortical processing in the mammalian brain
Authors: Birkner, Antje
Journal: (2019)
A versatile and Open-Source rapid LED switching system for One-Photon imaging and Photo-Activation
Authors: Battefeld, Arne and Popovic, Marko A and Van der Werf, Dirk and Kole, Maarten HP
Journal: Frontiers in cellular neuroscience (2019): 530
Gap junction coupling shapes the encoding of light in the developing retina
Authors: Caval-Holme, Franklin and Zhang, Yizhen and Feller, Marla B
Journal: Current Biology (2019): 4024--4035
A versatile and open-source rapid LED switching system for one-photon imaging and photo-activation
Authors: Battefeld, Arne and Popovic, Marko A and Van der Werf, Dirk and Kole, Maarten HP
Journal: Frontiers in cellular neuroscience (2018)
&alpha; V &beta; 3 Integrin regulates astrocyte reactivity
Authors: Lagos-Cabr&eacute;, Ra&uacute;l and Alvarez, Alvaro and Kong, Milene and Burgos-Bravo, Francesca and C&aacute;rdenas, Areli and Rojas-Mancilla, Edgardo and P&eacute;rez-Nunez, Ram&oacute;n and Herrera-Molina, Rodrigo and Rojas, Fabiola and Schneider, Pascal and others, undefined
Journal: Journal of Neuroinflammation (2017): 194
Ca 2+ signals initiate at immobile IP 3 receptors adjacent to ER-plasma membrane junctions
Authors: Thillaiappan, Nagendra Babu and Chavda, Alap P and Tovey, Stephen C and Prole, David L and Taylor, Colin W
Journal: Nature Communications (2017): 1505
In vivo deep two-photon imaging of neural circuits with the fluorescent Ca2+ indicator Cal-590
Authors: Tischbirek, Carsten H and Birkner, Antje and Konnerth, Arthur
Journal: The Journal of Physiology (2016)
Deep two-photon brain imaging with a red-shifted fluorometric Ca2+ indicator
Authors: Tischbirek, Carsten and Birkner, Antje and Jia, Hongbo and Sakmann, Bert and Konnerth, Arthur
Journal: Proceedings of the National Academy of Sciences (2015): 11377--11382