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| Calcium Indicators – Luminescent & Non-Luminescent |
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The aequorin complex comprises a 22 KD apoaequorin protein (APO), molecular oxygen
and the luminophore coelenterazine. When three Ca2+ ions bind to this complex,
coelenterazine is oxidized to coelenteramide, with a concomitant release of carbon
dioxide and blue light (See figure below). The approximately third-power dependence
of aequorin’s bioluminescence on Ca2+ concentration allows the measurement
of Ca2+ concentrations with a broad detection range from ~0.1 µM to >100
µM. Unlike fluorescent Ca2+ indicators, Ca2+-bound aequorin can be detected
without illuminating the sample, thereby eliminating interference from autofluorescence
and allowing simultaneous labeling with caged probes.
AnaSpec offers coelenterazine and several synthetic coelenterazine analogs for
reconstituting aequorin in cells that have been transfected with apoaequorin cDNA.
In addition to native coelenterazine, we also offer a few derivatives of coelenterazine
that confer different Ca2+ affinities and spectral properties on the aequorin
complex. Recombinant apoaequorin reconstituted with coelenterazine hcp is reported
to have the best luminescence overall, with both a high quantum yield and a fast
response time. However, intracellular reconstitution of aequorin from coelenterazine
analogs can be relatively slow. Aequorins containing the cp, f or h form of coelenterazine
exhibit 10–20 times stronger luminescence than that of apoaequorin reconstituted
with native coelenterazine. Coelenterazine cp has been used in HTS screening assay
for GPCRs.
Intracellular calibration of Ca2+ indicators may be achieved either by manipulating
Ca2+ levels inside cells using an ionophore or by releasing the indicator into
the surrounding medium of known Ca2+ concentration via detergent lysis of cells.
Along with fluorescent and luminescent Ca2+ detection reagents, AnaSpec also offers
several non-luminescent compounds for measuring and manipulating intracellular
and extracellular Ca2+. Amongst these, 5,5’-dimethyl BAPTA is the most powerful
Ca2+ chelator, which is also available in cell-permeable AM ester form. 5,5’-difluoro
BAPTA and its AM ester have been employed for optical imaging studies but are
most widely used for NMR analysis of Ca2+ in live cells and tissues.
AnaSpec is pleased to showcase a wide range of reagents for luminescent Ca2+ detection
and non-luminescent reagents for Ca2+ detection.
Click here for more information.
Luminescent Calcium Indicators
Non-luminescent calcium indicators
| Product |
Size |
Catalog
# |
| "BAPTA,
AM *UltraPure Grade*"
|
25 mg |
84071 |
| "BAPTA,
AM"
|
25 mg |
84070 |
| "5,5’-Difluoro
BAPTA, AM"
|
25 mg |
84074 |
| "5,5’-Dimethyl
BAPTA, AM"
|
25 mg |
84076 |
| "5,5’-Dinitro
BAPTA, AM"
|
25 mg |
84080 |
| "BAPTA,
tetrasodium salt"
|
100 mg |
84073 |
| "BAPTA,
tetrapotassium salt"
|
100 mg |
84072 |
| "5,5’-Dimethyl
BAPTA, tetrapotassium salt"
|
100 mg |
84077 |
| "5,5’-Difluoro
BAPTA, tetrapotassium salt"
|
100 mg |
84075 |
| "EGTA,
AM"
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10 mg |
84100 |
| "Pluronic®
F-127, 20% solution in DMSO"
|
10 mL |
84041 |
| Pluronic®
F-127 *Cell Culture Tested *
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10 g |
84040 |
| "Pluronic®
F-127, 10% solution in water"
|
100 mL |
84042 |
| "EGTA,
tetrasodium salt, 10 mM aqueous solution *UltraPure Grade*"
|
10 mL |
84097 |
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