Name: Cal Red™ R525/650 AM
Brand: AAT Bioquest
SKU: 20590
Availability: InStock

Cal Red™ R525/650 AM

The intracellular calcium flux assay is a widely used method for monitoring the activities of GPCRs and calcium channels. To quantify the intracellular calcium concentration, ratiometric fluorescent calcium indicators are preferred because the ratio is directly related to the calcium concentration and independent of the cell numbers and dye loading concentration. However, the most popular ratiometric calcium indicators (such as Fura-2 and Indo-1) have certain limitations such as lower sensitivity, UV excitation, and not compatible with HTS screening filter set. Cal Red™ R525/650 has been developed as a new 488 nm-excitable ratiometric fluorescence calcium indicator. Cal Red™ R525/650 is weakly fluorescent, and once enters cells, the lipophilic AM blocking groups are cleaved by intracellular esterase, resulting in a negatively charged fluorescent dye retained well in cells with excitation close to 488 nm and two emissions at 525 nm and 650 nm. When cells are stimulated with a bioactive compound, the receptor initiates the release of intracellular calcium, which is chelated by Cal Red™ R525/650. The emission signal is increased at 525 nm and decreased at 650 nm when excited at 488 nm. The excitation and emission wavelength of Cal Red™ R525/650 are compatible with common filter sets with minimal damage to cells, making it a robust tool for evaluating and screening GPCR agonists and antagonists as well as calcium channel targets.

Graph illustrates signal-to-noise ration (SNR) x 100%. ATP-stimulated calcium response of endogenous P2Y receptor in CHO-K1 cells incubated with Cal Red R525/650. ATP (50 uL/well) was added by FlexStation3 (Molecular Devices) to achieve the final indicated concentrations.

Protocol

COO

COA

Catalog	Size	Price	Quantity
20590	1 mg	Price
20591	10x50 ug	Price

Citations

View all 12 citations: Citation Explorer

Transplantation of Gene-Edited Hematopoietic Stem Cells Rescues Neuronal and Cardiac Complications in a Mouse Model of Friedreich's Ataxia

Authors:

Sivakumar, Anusha and Corl, Alexis N and Solis, Angelyn B and El-Hachem, Lilas Rony and Murthy, Rishika and Badell-Grau, Rafael Andres and Wan, Rita and Thai, Eric and Khare, Veenita and Cherqui, Stephanie

Journal:

MOLECULAR THERAPY (2024): 419--420

Gene editing improves endoplasmic reticulum-mitochondrial contacts and unfolded protein response in Friedreich’s ataxia iPSC-derived neurons

Authors:

Mishra, Priyanka and Sivakumar, Anusha and Johnson, Avalon and Pernaci, Carla and Warden, Anna S and El-Hachem, Lilas Rony and Hansen, Emily and Badell-Grau, Rafael A and Khare, Veenita and Ramirez, Gabriela and others,

Journal:

Frontiers in Pharmacology (2024): 1323491

Ultrasound-mediated spatial and temporal control of engineered cells in vivo

Authors:

Ivanovski, Filip and Me{\v{s}}ko, Maja and Lebar, Tina and Rupnik, Marko and Lain{\v{s}}{\v{c}}ek, Du{\v{s}}ko and Gradi{\v{s}}ek, Miha and Jerala, Roman and Ben{\v{c}}ina, Mojca

Journal:

Nature Communications (2024): 7369

Synchronous force and Ca2+ measurements for repeated characterization of excitation-contraction coupling in human myocardium

Authors:

Sun, Zhengwu and Lu, Kun and Kamla, Christine and Kameritsch, Petra and Seidel, Thomas and Dendorfer, Andreas

Journal:

Communications Biology (2024): 220

Foxp3-mediated blockage of ryanodine receptor 2 underlies contact-based suppression by regulatory T cells

Authors:

Wang, Xiaobo and Geng, Shuang and Meng, Junchen and Kang, Ning and Liu, Xinyi and Xu, Yanni and Lyu, Huiyun and Xu, Ying and Xu, Xun and Song, Xinrong and others,

Journal:

The Journal of Clinical Investigation (2023)

References

View all 12 references: Citation Explorer

Ratiometric analysis of fura red by flow cytometry: a technique for monitoring intracellular calcium flux in primary cell subsets

Authors:

Wendt ER, Ferry H, Greaves DR, Keshav S.

Journal:

PLoS One (2015): e0119532

A flow cytometric comparison of Indo-1 to fluo-3 and Fura Red excited with low power lasers for detecting Ca(2+) flux

Authors:

Bailey S, Macardle PJ.

Journal:

J Immunol Methods (2006): 220

Use of co-loaded Fluo-3 and Fura Red fluorescent indicators for studying the cytosolic Ca(2+)concentrations distribution in living plant tissue

Authors:

Walczysko P, Wagner E, Albrechtova JT.

Journal:

Cell Calcium (2000): 23

Monitoring calcium in outer hair cells with confocal microscopy and fluorescence ratios of fluo-3 and fura-red

Authors:

Su ZL, Li N, Sun YR, Yang J, Wang IM, Jiang SC.

Journal:

Shi Yan Sheng Wu Xue Bao (1998): 323

Problems associated with using Fura-2 to measure free intracellular calcium concentrations in human red blood cells

Authors:

Blackwood AM, Sagnella GA, Mark and u ND, MacGregor GA.

Journal:

J Hum Hypertens (1997): 601

Physical properties

Dissociation constant (K_d, nM)	330
Molecular weight	~1100
Solvent	DMSO

Storage, safety and handling

Certificate of Origin	Download PDF
H-phrase	H303, H313, H333
Hazard symbol	XN
Intended use	Research Use Only (RUO)
R-phrase	R20, R21, R22
Storage	Freeze (< -15 °C); Minimize light exposure
UNSPSC	12352200

Instrument settings

Fluorescence microscope
Excitation	FITC
Emission	FITC
Recommended plate	Black wall/clear bottom

Fluorescence microplate reader
Excitation	490
Emission	525, 660
Cutoff	515, 630
Recommended plate	Black wall/clear bottom
Instrument specification(s)	Bottom read mode/Programmable liquid handling

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Page updated on October 13, 2025