5-羧基熒光素是制備水解穩(wěn)定熒光共軛物的有用試劑,也是合成其它熒光素衍生試劑的有用起始材料。它是通過(guò)苯三羧酸酐與間苯二酚和氯化鋅反應(yīng)制備的5-和6-異構(gòu)體的混合物。盡管這些同分異構(gòu)體具有幾乎相同的性質(zhì),但當(dāng)與其他分子結(jié)合時(shí),在共軛極性、內(nèi)部熒光猝滅以及相關(guān)羅丹明標(biāo)記試劑的情況下,已觀察到標(biāo)記特異性的差異。此外,熒光素衍生物的多步合成制備需要具有異構(gòu)體純度的起始原料,以便反應(yīng)產(chǎn)物易于純化和鑒定。
5-FAM contains a carboxylic acid that can be used to react with primary amines via carbodiimide activation of the carboxylic acid. Fluorescein is the most common fluorescent derivatization reagent for labeling biomolecules. In addition to its relatively high absorptivity, excellent fluorescence quantum yield, and good water solubility, fluorescein has an excitation maximum that closely matches the 488 nm spectral line of the argon-ion laser.