Cal-520FF(TM), potassium salt

10x50 µg. Ex: 492 nm. Em: 514 nm. Soluble in: Water. Cal-520T provides a robust homogeneous fluorescence-based assay tool for detecting intracellular calcium mobilization. Cal-520T 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-520T AM which can cross cell membrane. Once inside the cell, the lipophilic blocking groups of Cal 520T 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-520T. The characteristics of its long wavelength, high sensitivity, and >100 times fluorescence enhancement, make Cal-520T AM an ideal indicator for the measurement of cellular calcium. The high S/N ratio and better intracellular retention make the Cal-520T calcium assay a robust tool for evaluating GPCR and calcium channel targets as well as for screening their agonists and antagonists. Cal-520T sodium or potassium salt is the hydrolyzed salt of Cal-520T AM in cells. It selectively binds to calcium ion, and has the fluorescence that is strongly dependent on calcium concentration. Compared to other Cal-520T indicators, Cal-520FFT has the lowest affinity to calcium with Kd ~ 10 uM.