Fura-2, an aminopolycarboxylic acid, is a ratiometric fluorescent dye which binds to free intracellular calcium. It was the first widely used dye for calcium imaging, and remains very popular. Fura-2 is excited at 340nm and 380nm of light, and the ratio of the emissions at those wavelengths is directly related to the amount of intracellular calcium. Regardless of the presence of calcium, Fura-2 emits at 510nm of light. The use of the ratio automatically cancels out confounding variables, such as variable dye concentration and cell thickness, making Fura-2 one of the most appreciated tools to quantify calcium levels. The high photon yield of fura-2 allowed the first real time (video rate) measurements of calcium inside living cells in 1986. More recently, genetically-encoded calcium indicators based on spectral variants of the green fluorescent protein, such as Cameleons, have supplemented the use of Fura-2 and other small molecule dyes for calcium imaging, but Fura-2 remains faster.

CAS：113694-64-7
中文别名：FURA 2 五钾盐;2-[6-[双(羧甲基)氨基]-5-[2-[2-[双(羧甲基)氨基]-5-甲基苯氧基]乙氧基]-2-苯并呋喃基]-5-恶唑羧酸五钾盐;
英文别名：Fura-2,pentapotassium salt;FURA 2 PENTAPOTASSIUM SALT;
分子式：C29H22K5N3O14
分子量：831.988
精确质量：830.929
Psa：264.76
Logp：-4.1701

PubChem号：24894731
MDL号：MFCD00083328

沸点：983.5ºC at 760 mmHg
闪点：548.6ºC
储存条件：-20ºC
蒸汽压：0mmHg at 25°C