fura 2 (potassium salt)

Fura-2 potassium salt 是一种常用的紫外光激发性荧光探针，可用于细胞内钙离子成像。

Rhod-2 (potassium salt) is a water-soluble, red fluorescent calcium indicator. It exhibits a significant shift in fluorescence intensity upon calcium binding (ex max = 549 nm; calcium-free v. ex em max = 552 581 nm; calcium-bound). Unlike the UV-excitable indicators fura-2 and indo-1 , there is no accompanying spectral shift.

Fura-FF AM is a cell-permeable acetoxymethyl ester of the fluorescence calcium indicator fura-FF (potassium salt) . As fura-FF AM enters cells, it is hydrolyzed by intracellular esterases to produce fura-FF. Fura-FF is a difluorinated derivative of the calcium indicator fura-2 . Unlike, fura-2, fura-FF has negligible magnesium sensitivity, thus reducing interference from this cation. Fura-FF also has a higher calcium dissociation constant than fura-2 (Kd(calcium) = 6 and 0.14 μM, respectively). However, the spectral properties of fura-FF and fura-2 are similar with fura-FF displaying excitation emission spectra of 365 514 nm in the absence of calcium, with a shift to 339 507 nm in the presence of a high calcium concentration. Low affinity calcium dyes, including fura-FF, are preferred for studying compartments with high concentrations of calcium, such as mitochondria, or in cell systems that have relatively low calcium buffering capacities, such as neuronal dendrites and spines.