A new class of calcium specific fluorescent indicator dyes having visible excitation and emission wavelengths combine at least one tricyclic chromophore with a tetracarboxylate parent CA2+ chelating compound having the octacoordinate pattern of liganding groups characteristic of BAPTA to give a rhodamine-like or fluorescein-like fluorophore. Binding of calcium2+ increases the fluorescence of the new compounds by up to 40-fold. The calcium2+ dissociation constants are in the range 0.37-2.3 microM, so that the new indicators give better resolution of high [CA2+] levels than were previously obtainable with predecessor compounds such as quin-2 or fluo-2. The visible excitation wavelengths of the new compounds are more convenient for fluorescent microscopy and flow cytometry than the UV required by previous indicators.
一类具有可见激发和发射波长的新型
钙特异性荧光指示剂
染料将至少一种
三环发色团与四
羧酸母体 CA2+ 螯合化合物结合在一起,该化合物具有 BA
PTA 特有的八配位配位基团模式,从而产生类似
罗丹明或
荧光素的荧光团。
钙2+的结合可使新化合物的荧光增加 40 倍。
钙2+的解离常数在 0.37-2.3 微摩尔范围内,因此新指示剂对高浓度[CA2+]的分辨能力比以前的前代化合物(如 quin-2 或 fluo-2)更强。与以前的指示剂所需的紫外波长相比,新化合物的可见光激发波长更便于荧光显微镜和流式细胞仪的使用。