Calbryte(TM) 520L AM

10x50 µg. Ex: 492 nm. Em: 514 nm. Soluble in: DMSO. The intracellular calcium flux assay is a widely used method in monitoring signal transduction pathways and high throughput screening of G protein-coupled receptors (GPCRs) and calcium channel targets. Followed by Fluo-3 being introduced in 1989, Fluo-4, Fluo-8 and Cal-520 were later developed with improved signal/background ratio, and became the widely used Ca2+ indicators for confocal microscopy, flow cytometry and high throughput screening applications. However, there are still a few severe problems with Fluo-4. For example, as for Fluo-3, in all most all the intracellular calcium assays with Fluo-4 AM, probenecid is required to prevent the cell-loaded Fluo-4 from leaking out of cells. The use of probenecid with Fluo-4-based calcium assays compromises the assay results since probenecid is well-documented to have a variety of complicated cellular effects. Calbryte 520L, AM is a new fluorescent and cell-permeable calcium indicator. Like other dye AM cell loading, Calbryte 520L AM ester is non-fluorescent and once gets inside the cell, it is hydrolyzed by intracellular esterase and gets activated. The activated indicator is a polar molecule that is no longer capable of freely diffusing through cell membrane, essentially trapped inside cells. Calbryte 520L has low affinity to calcium ion with Kd ~100 uM. Calbryte 520L produces bright fluorescence signal in the presence of calcium ion in high concentration. It has the identical excitation and emission wavelength as Fluo-4, thus the same Fluo-4 assay settings can be readily applied to Calbryte 520L-based calcium assays.