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Cal-520® alkyne

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Physical properties
Molecular weight905.77
Spectral properties
Excitation (nm)492
Emission (nm)515
Quantum yield0.751
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
Excitation (nm)
Emission (nm)
Quantum yield
Cal-520® alkyne is an excellent building block that can be readily used to prepare a calcium-sensitive bioconjugate for monitoring calcium change spatially for a specific target. It can be conjugated to azido-containing biomolecules via the well-known click chemistry. Calcium measurement is critical for numerous biological and neurological investigations. Fluorescent probes showing spectral responses upon binding calcium have enabled researchers to investigate changes in intracellular free calcium concentrations using fluorescence microscopy, flow cytometry, fluorescence spectroscopy, and fluorescence microplate readers. Cal-520® has been proven to be one of the best-known green fluorescent calcium indicators.


Common stock solution preparation

Table 1. Volume of DMSO needed to reconstitute specific mass of Cal-520® alkyne 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 mM110.403 µL552.017 µL1.104 mL5.52 mL11.04 mL
5 mM22.081 µL110.403 µL220.807 µL1.104 mL2.208 mL
10 mM11.04 µL55.202 µL110.403 µL552.017 µL1.104 mL

Molarity calculator

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Spectral properties

Excitation (nm)492
Emission (nm)515
Quantum yield0.751

Product Family

NameExcitation (nm)Emission (nm)Quantum yield
Cal-520®, AM4925150.751



View all 50 references: Citation Explorer
Simultaneous Acquisition of Mitochondrial Calcium Retention Capacity and Swelling to Measure Permeability Transition Sensitivity.
Authors: Mendoza, Arielys M and Karch, Jason
Journal: Methods in molecular biology (Clifton, N.J.) (2022): 129-140
The microtubule network enables Src kinase interaction with the Na,K-ATPase to generate Ca2+ flashes in smooth muscle cells.
Authors: Rognant, Salomé and Kravtsova, Violetta V and Bouzinova, Elena V and Melnikova, Elizaveta V and Krivoi, Igor I and Pierre, Sandrine V and Aalkjaer, Christian and Jepps, Thomas A and Matchkov, Vladimir V
Journal: Frontiers in physiology (2022): 1007340
Effects of pyriproxyfen on zebrafish brain mitochondria and acetylcholinesterase.
Authors: Azevedo, Rafael D S and Falcão, Kivia V G and Assis, Caio R D and Martins, Regildo M G and Araújo, Marlyete C and Yogui, Gilvan T and Neves, Jorge L and Seabra, Gustavo M and Maia, Maria B S and Amaral, Ian P G and Leite, Ana C R and Bezerra, Ranilson S
Journal: Chemosphere (2021): 128029
Cationic Channel TRPV2 Overexpression Promotes Resistance to Cisplatin-Induced Apoptosis in Gastric Cancer Cells.
Authors: Laurino, Simona and Mazzone, Pellegrino and Ruggieri, Vitalba and Zoppoli, Pietro and Calice, Giovanni and Lapenta, Antonella and Ciuffi, Mario and Ignomirelli, Orazio and Vita, Giulia and Sgambato, Alessandro and Russi, Sabino and Falco, Geppino
Journal: Frontiers in pharmacology (2021): 746628
Assessment of Mitochondrial Ca2+ Uptake.
Authors: Deak, András T and Jean-Quartier, Claire and Bondarenko, Alexander I and Groschner, Lukas N and Malli, Roland and Graier, Wolfgang F and Waldeck-Weiermair, Markus
Journal: Methods in molecular biology (Clifton, N.J.) (2021): 173-191
Analysis of Mitochondrial Calcium Retention Capacity in Cultured Cells: Permeabilized Cells Versus Isolated Mitochondria.
Authors: Jang, Sehwan and Chapa-Dubocq, Xavier R and Fossati, Silvia and Javadov, Sabzali
Journal: Frontiers in physiology (2021): 773839
The Use of Complementary Luminescent and Fluorescent Techniques for Imaging Ca2+ Signaling Events During the Early Development of Zebrafish (Danio rerio).
Authors: Webb, Sarah E and Miller, Andrew L
Journal: Methods in molecular biology (Clifton, N.J.) (2019): 73-93
Mitochondria-coupled glucose phosphorylation develops after birth to modulate H2 O2 release and calcium handling in rat brain.
Authors: de-Souza-Ferreira, Eduardo and Rios-Neto, Izac Miranda and Martins, Eduarda Lopes and Galina, Antonio
Journal: Journal of neurochemistry (2019): 624-640
Ischemia time impacts on respiratory chain functions and Ca2+-handling of cardiac subsarcolemmal mitochondria subjected to ischemia reperfusion injury.
Authors: Leistner, Marcus and Sommer, Stefanie and Kanofsky, Peer and Leyh, Rainer and Sommer, Sebastian-Patrick
Journal: Journal of cardiothoracic surgery (2019): 92
Chloride channel blocker IAA-94 increases myocardial infarction by reducing calcium retention capacity of the cardiac mitochondria.
Authors: Ponnalagu, Devasena and Hussain, Ahmed Tafsirul and Thanawala, Rushi and Meka, Jahnavi and Bednarczyk, Piotr and Feng, Yansheng and Szewczyk, Adam and GururajaRao, Shubha and Bopassa, Jean C and Khan, Mahmood and Singh, Harpreet
Journal: Life sciences (2019): 116841