Membrane-impermeant calcium indicator that can be loaded into cells via microinjection or scrape loading.    Kd: 250 nM  &lamba;Ex/&lamba;Em (no Ca2 ) = 349/482 nm  &lamba;Ex/&lamba;Em (high Ca2 ) = 331/398 nm  ε (349 nm, no Ca2 ) = 34,000 M-1cm-1  Light yellow solid soluble in DMSO  Store at 4°C and protect from light, especially in solution  C32 H46N8 O12  MW: 735