potassium

D-Luciferin potassium (D-Luciferin K Salt) is a popular bioluminescent substrate of luciferase in the presence of ATP.

Fluo-3FF is a fluorescent calcium indicator. It is a di-fluorinated analog of Fluo-3 that displays about a 100-fold lower affinity than Fluo-3 for calcium (Kds = 42 and 0.4 μM, respectively). Low affinity calcium indicators are particularly useful for studying compartments with high concentrations of calcium, such as endoplasmic reticulum, where high affinity dyes will be insensitive to luminal fluctuations. Fluo-3FF has excitation/emission maxima of approximately 506 and 526 nm, respectively.

Potassium 2-naphthylamine-6,8-disulfonic acid is a chemical compound utilized in the synthesis of dyes, pharmaceuticals, and agricultural chemicals [1].

Cal Green 1 is a cell-impermeant fluorescent calcium indicator that is characterized by high quantum yield and low phototoxicity. Its peak excitation and emission wavelengths (506 and 531 nm, respectively) are comparable to standard fluorescein dyes, making Cal Green 1 appropriate for fluorescent microscopy. Cal Green 1 is ~5-fold brighter than fluo-3 at saturating calcium levels.

Rhod-2 (potassium salt) is a water-soluble, red fluorescent calcium indicator. It exhibits a significant shift in fluorescence intensity upon calcium binding (ex max = 549 nm; calcium-free v. ex/em max = 552/581 nm; calcium-bound). Unlike the UV-excitable indicators fura-2 and indo-1 , there is no accompanying spectral shift.

Indo-1 (potassium salt) is a ratiometric fluorescent calcium indicator. It is ideal for analyses using flow cytometry, as it uses a single excitation source, typically 349-364 nm light from an argon-ion laser. The emission maximum shifts from 475-485 nm without calcium to 400-410 nm when Indo-1 (potassium salt) binds calcium. Indo-1 (potassium salt) is prone to photobleaching, which limits its usefulness in methods involving microscopy.

MeCY5-NHS ester (potassium) is a reactive dye designed for labeling proteins and nucleic acids.

Fura-2 is a ratiometric fluorescent calcium indicator that can be used to detect calcium in cells. [1] It is a pentacarboxylate that displays excitation maxima of 340 and 380 nm at high and low calcium concentrations, respectively, when the emission is fixed at 510 nm, enabling determination of ratiometric measurements of calcium influx in live cells.

Quin-2 is a high-affinity fluorescent calcium indicator (Kd = 115 nM for calcium). It displays high selectivity for calcium, as it is not affected by sodium gradients, membrane potential, or intracellular pH. High affinity probes like quin-2 are ideal for monitoring low levels of calcium, as are found in resting cells. Loadings of up to 2 mM quin-2 are without serious toxic effects, so quin-2 may be used to buffer intracellular calcium transients. Excitation/emission maxima for quin-2 are 339 and 492 nm, respectively.

Fluo-3 (potassium salt) is a fluorescent calcium indicator commonly used in flow cytometry and cell-based experiments to detect changes in intracellular calcium levels. Its absorption maximum at 506 nm makes it compatible with excitation at 488 nm by argon-ion laser sources. Fluo-3 provides intense fluorescence upon binding calcium, detected at a maximum emission at 526 nm which can be monitored by FL1 (green, 525 nm band pass) sensors in flow cytometry.

Rhod-5N is a low affinity fluorescent calcium probe (Kd = 320 μM). Low affinity calcium indicators are particularly useful for studying compartments with high concentrations of calcium, such as endoplasmic reticulum, where high affinity dyes will be insensitive to luminal fluctuations. Rhod-5N has excitation/emission maxima of approximately 551 and 576 nm, respectively

Rhod-FF is a difluorinated analog of the cell-impermeant calcium indicator rhod-2. It has a very low affinity for calcium (Kd = 320 μM). Low affinity calcium indicators are particularly useful for studying compartments with high concentrations of calcium, such as endoplasmic reticulum, where high affinity dyes will be insensitive to luminal fluctuations. Rhod-FF has excitation/emission maxima of approximately 552 and 580 nm, respectively.

bis-ANS is a high-affinity non-covalent extrinsic fluorescent dye used to analyze protein conformation.[1] Its predominant interaction with proteins is through its hydrophobic phenyl and naphthyl rings.[2] bis-ANS has an excitation maxima of 390 nm.[3] It has an emission maximum of 523 nm when free in solution but undergoes a blue shift with an increase in fluorescence intensity when bound to protein; for example, when bound to intestinal fatty acid binding protein (FAPB2) it has emission maxima of 484-496 nm. bis-ANS has been used to label mechanically damaged neurons in acute brain slices.4 It also potently inhibits microtubule assembly.[5],[6]

Mag-Indo-1 tetrapotassium salt is a cell-impermeable fluorescent probe designed for detecting Mg2+ [1].

Lucifer Yellow CH dipotassium, a high-intensity fluorescent probe featuring free hydrazyl groups, reacts with fatty aldehydes at room temperature and functions as a biological tracer for neuronal branching, regeneration, gap junction detection, and characterization, as well as selective cell ablation following aldehyde fixation. It exhibits peak excitation and emission wavelengths of 430 nm and 540 nm, respectively [1] [2].

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. Fluo-3 and Fluo-4 are most commonly used among the visible light-excitable calcium indicators. Fluo-4, pentapotassium salt is an analog of fluo-3 with the two chlorine substituents replaced by fluorines, which results in increased fluorescence excitation at 488 nm and consequently higher fluorescence signal levels.

Lucifer Yellow Iodoacetamide Dipotassium is a thiol-reactive (sulfhydryl-reactive) fluorescent tracer utilized for labeling proteins.

Tetrapotassium BTC is a calcium indicator with low affinity (Kd approximately 7-26 µM) that offers favorable characteristics for cellular calcium imaging, such as extended excitation wavelengths (400/485 nm), minimal sensitivity to Mg2+, and precise ratiometric measurement [1].

Fura-FF pentapotassium salt is a low affinity calcium fluorescent dye (Ex/Em: 365/514 nm, no calcium; 339/507 nm, high calcium).

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. Fluo-3, pentapotassium salt is most commonly used among the visible light-excitable calcium indicators.

BAPTA, tetrapotassium salt is a Ca2+ chelator.

BAPTA-AM is a calcium chelator that is cell-permeable and selective, blocking hERG, hKv1.3, and hKv1.5 channels (IC50=1.3/1.45/1.23 μM). BAPTA-AM has a 105-fold higher affinity for Ca2+ than for Mg2+, and can be used for the role of calcium in cell signaling.

Fura-FF AM is a cell-permeable acetoxymethyl ester of the fluorescence calcium indicator fura-FF (potassium salt) . As fura-FF AM enters cells, it is hydrolyzed by intracellular esterases to produce fura-FF. Fura-FF is a difluorinated derivative of the calcium indicator fura-2 . Unlike, fura-2, fura-FF has negligible magnesium sensitivity, thus reducing interference from this cation. Fura-FF also has a higher calcium dissociation constant than fura-2 (Kd(calcium) = 6 and 0.14 μM, respectively). However, the spectral properties of fura-FF and fura-2 are similar with fura-FF displaying excitation/emission spectra of 365/514 nm in the absence of calcium, with a shift to 339/507 nm in the presence of a high calcium concentration. Low affinity calcium dyes, including fura-FF, are preferred for studying compartments with high concentrations of calcium, such as mitochondria, or in cell systems that have relatively low calcium buffering capacities, such as neuronal dendrites and spines.

IPG-4 AM, a membrane-permeable fluorescent indicator, specifically binds to potassium ions (K+) with a dissociation constant (Kd) of 7 mM. This compound exhibits excitation and emission maxima (λ) at 525 nm and 545 nm, respectively, and displays a 100:1 selectivity for K+ over sodium ions (Na+). It is utilized for real-time detection of intracellular K+ levels, as well as monitoring extracellular K+ changes in vivo.

ING-2 AM is a membrane-permeable fluorescent indicator specifically designed for sodium ions (Na+), exhibiting a binding affinity with a dissociation constant (Kd) of 20 mM. With excitation and emission maxima (λ) at 525 nm and 545 nm respectively, this compound achieves a 20-fold selectivity over potassium ions (K+). It is utilized both in vitro and in situ to monitor real-time sodium influx.

Proflavine Hemisulfate (3,6-Diaminoacridine hemisulfate) is the hemisulfate salt form of proflavine, an acridine-derived fluorescent contrast and disinfectant agent that can potentially be used for cellular imaging and antiseptic purposes.

3,6-diacetoxy Phthalonitrile is a fluorescent probe for monitoring intracellular pH by flow cytometry in living cells. It rapidly crosses cell membranes and is cleaved by cytosolic esterases to form the fluorescent pH indicator 2,3-dicyano-hydroquinone (DCH), which is excited at UV wavelengths. DCH can be excited at 351 nm, with pH-dependent emission in the range of 450-476 nm (pH 5.0-10.0) using a potassium-based buffer.