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Cal-520®, potassium salt

Cal-520® provides a robust homogeneous fluorescence-based assay tool for detecting intracellular calcium mobilization. Cal-520® AM is a new fluorogenic calcium-sensitive dye with a significantly improved signal to noise ratio and intracellular retention compared to the existing green calcium indicators (such as Fluo-3 AM and Fluo-4 AM). Cells expressing a GPCR or calcium channel of interest that signals through calcium can be preloaded with Cal-520® AM which can cross cell membrane. Once inside the cell, the lipophilic blocking groups of Cal-520™ AM are cleaved by esterases, resulting in a negatively charged fluorescent dye that stays inside cells. Its fluorescence is greatly enhanced upon binding to calcium. When cells stimulated with agonists, the receptor signals the release of intracellular calcium, which significantly increase the fluorescence of Cal-520®. The characteristics of its long wavelength, high sensitivity, and >100 times fluorescence enhancement, make Cal-520® AM an ideal indicator for the measurement of cellular calcium. The high S/N ratio and better intracellular retention make the Cal-520® calcium assay a robust tool for evaluating GPCR and calcium channel targets as well as for screening their agonists and antagonists. Cal-520® sodium or potassium salt is the hydrolyzed salt of Cal-520® AM in cells. It selectively binds to calcium ion, and has the fluorescence that is strongly dependent on calcium concentration.

Calculators

Common stock solution preparation

Table 1. Volume of Water needed to reconstitute specific mass of Cal-520®, 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 mM108.568 µL542.841 µL1.086 mL5.428 mL10.857 mL
5 mM21.714 µL108.568 µL217.136 µL1.086 mL2.171 mL
10 mM10.857 µL54.284 µL108.568 µL542.841 µL1.086 mL

Molarity calculator

Enter any two values (mass, volume, concentration) to calculate the third.

Mass (Calculate)Molecular weightVolume (Calculate)Concentration (Calculate)Moles
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Spectrum

Citations

View all 101 citations: Citation Explorer
Enhanced long-term potentiation in the anterior cingulate cortex of tree shrew
Authors: Song, Qian and Li, Xu-Hui and Lu, Jing-Shan and Chen, Qi-Yu and Liu, Ren-Hao and Zhou, Si-Bo and Zhuo, Min
Journal: Philosophical Transactions B (2024): 20230240
Activation of the glutamatergic cingulate cortical-cortical connection facilitates pain in adult mice
Authors: Li, Xu-Hui and Shi, Wantong and Chen, Qi-Yu and Hao, Shun and Miao, Hui-Hui and Miao, Zhuang and Xu, Fang and Bi, Guo-Qiang and Zhuo, Min
Journal: Communications Biology (2023): 1247
L-type Ca2+ channel recovery from inactivation in rabbit atrial myocytes
Authors: Martinez-Hernandez, Elizabeth and Blatter, Lothar A and Kanaporis, Giedrius
Journal: Physiological Reports (2022): e15222
Dendritic spikes in apical oblique dendrites of cortical layer 5 pyramidal neurons
Authors: Casta{\~n}ares, Michael Lawrence G and Stuart, Greg J and Daria, Vincent R
Journal: bioRxiv (2020)
Multiphoton minimal inertia scanning for fast acquisition of neural activity signals
Authors: Schuck, Renaud and Go, Mary Ann and Garasto, Stefania and Reynolds, Stephanie and Dragotti, Pier Luigi and Schultz, Simon R
Journal: Journal of neural engineering (2018): 025003
Page updated on December 17, 2024

Ordering information

Price
Unit size
10x50 ug
1 mg
Catalog Number
2114021141
Quantity
Add to cart

Additional ordering information

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Physical properties

Dissociation constant (Kd, nM)320

Molecular weight

921.08

Solvent

Water

Spectral properties

Excitation (nm)

492

Emission (nm)

515

Quantum yield

0.751

Storage, safety and handling

Certificate of OriginDownload PDF
H-phraseH303, H313, H333
Hazard symbolXN
Intended useResearch Use Only (RUO)
R-phraseR20, R21, R22

Storage

Freeze (< -15 °C); Minimize light exposure
UNSPSC12352200
ATP-stimulated calcium responses of endogenous P2Y receptor in CHO-K1 cells incubated with Cal-520&trade; AM (red curve), or Fluo-4 AM (blue curve) respectively with (left) or without probenecid (right) under the same conditions. CHO-K1 cells were seeded overnight at 50,000 cells per 100 &micro;L per well in a Costar black wall/clear bottom 96-well plate. 100 &micro;L of 5 &micro;M Fluo-4 AM or Cal 520&trade; AM in HHBS (with or without 2.5 mm probenecid) was added into the cells, and the cells were incubated at 37 &deg;C for&nbsp;1 hour. ATP (50 &mu;L/well) was added using FlexSation to achieve the final indicated concentrations.
ATP-stimulated calcium responses of endogenous P2Y receptor in CHO-K1 cells incubated with Cal-520&trade; AM (red curve), or Fluo-4 AM (blue curve) respectively with (left) or without probenecid (right) under the same conditions. CHO-K1 cells were seeded overnight at 50,000 cells per 100 &micro;L per well in a Costar black wall/clear bottom 96-well plate. 100 &micro;L of 5 &micro;M Fluo-4 AM or Cal 520&trade; AM in HHBS (with or without 2.5 mm probenecid) was added into the cells, and the cells were incubated at 37 &deg;C for&nbsp;1 hour. ATP (50 &mu;L/well) was added using FlexSation to achieve the final indicated concentrations.
ATP-stimulated calcium responses of endogenous P2Y receptor in CHO-K1 cells incubated with Cal-520&trade; AM (red curve), or Fluo-4 AM (blue curve) respectively with (left) or without probenecid (right) under the same conditions. CHO-K1 cells were seeded overnight at 50,000 cells per 100 &micro;L per well in a Costar black wall/clear bottom 96-well plate. 100 &micro;L of 5 &micro;M Fluo-4 AM or Cal 520&trade; AM in HHBS (with or without 2.5 mm probenecid) was added into the cells, and the cells were incubated at 37 &deg;C for&nbsp;1 hour. ATP (50 &mu;L/well) was added using FlexSation to achieve the final indicated concentrations.