Asante Potassium Green
- #3602 APG-2 (AM) 500 ug... $210 Add to Cart
- #3612 APG-2 (AM) 10 x 50 ug... $250 Add to Cart
- #3622 APG-2 (salt) 250 ug... $120 Add to Cart
- #3632 APG-2 (AM) 5 x 500 ug... $1000 Add to Cart
- #3642 APG-2(AM) 2 x 50 ug... $65 Add to Cart
- #3652 APG-2 (salt) 2 x 25 ug... $30 Add to Cart
Asante Potassium Green is a fluorescent indicator with a useful Kd for measuring cytosolic K+ concentration. It loads readily and is excited by visible light. Although non-ratiometric, its large fluorescence dynamic range allows sensing of even small changes in K+ concentration. Optimal excitation occurs at 517 nm, but the indicator can also be excited at the conventional wavelength of 488 nm. APG-1 works well with 2-photon excitation at near-infrared wavelengths and is quite resistant to photobleaching. Like its sodium counterpart, it is useful for confocal microscopy, flow cytometry, and screening. Asante Potassium Green-1 has been replaced by our Asante Potassium Green-2 with improved kd.
Excitation: 488 nm (excitation maxima at 517 nm)
Emission: 540 nm
kd: 54 mM
Solubility: H2O (salt form), DMSO (AM form)
Molecular Weight: 1100 g/mol
Asante Potassium Green 1 emission titrattion in TMA+CL-.
Figure 3.1 Response of intracellular APG-1 to K+: REF52 fibroblasts loaded with APG-1 (through incubation with AM ester) were maintained in 145 mM N-methyl-D-glucamine (NMG) gluconate. To deplete cells of K+ and Na+, the cells were treated with 50 µM amphotericin-B (a polyene microbial metabolite that markedly increases membrane permeability to monovalent ions; e.g., Na+ K+, H+ and Cl-). Increments of KCl were added to raise potassium concentration ([K+]) in the extracellular medium to various levels (5 , 15, 45, and 145 mM, as indicated in the figure). After each increment, as the intracellular and extracellular [K+] equilibrated, a corresponding increase in intracellular indicator fluorescence was observed. At the end of the experiment, an aliquot of NaCl was added to raise [Na+] to 10 mM, a typical cytosolic value. The added Na+ only slightly affected the fluorescence of APG-1. The response shown is the average from 45 cells. [J. Kao, Univ. of Maryland Medical School]
APG-1 (AM) cell loading procedure for the experiment of Figures 3.1: (This procedure should not be treated as a general loading protocol for APG-1. Please refer to our AM Ester Loading guidelines.)
- 1-5 μM of APG-1 (AM) is typical concentration range for loading
- The sample Is prepared with ~75 ppm Pluronic for dispersing the dye into the incubation buffer.
- For these experiments, the buffer consisted of HCO3-DMEM with 10% fetal bovine serum (FBS) and kept under 5% CO2 atmosphere.
- Loading time varied from 45 minutes to 70 minutes.
- Fluorescence imaging experiments were conducted in HBSS.
[J. Kao, Univ. of Maryland Medical School].
Figure 3.1 Methods: REF52 fibroblasts were incubated at room temperature for 60 minutes with 2 µM Asante Potassium Green 1 AM ester in bicarbonate-buffered Dulbecco’s Modified Eagle Medium (DMEM) supplemented with 10% fetal bovine serum, under an atmosphere of 5% CO2/95% O2; the medium also contained 0.0075% (w/v) of the nonionic surfactant, Pluoronic F-127. The cells were then transferred into 145 mM NMG gluconate (pH 7.4). Amphotericin B was prepared as a 50 mM solution in DMSO; 1,000-fold dilution into the aqueous medium gave the desired final concentration of 50 µM. Appropriate volumes of 4.0 M KCl or NaCl were added to achieve the desired concentrations in the aqueous medium. Indicator fluorescence was excited at 488 nm; fluorescence images were acquired with a cooled CCD camera.
[J. Kao, Univ. of Maryland Medical School]