New Fluorogenic Reagent Having Halogenobenzofurazan Structure for Thiols: 4-(Aminosulfonyl)-7-fluoro-2,1,3-benzoxadiazole

Article abstract of DOI:10.1021/ac00277a044

4-(Aminosulfonyl)-7-fluoro-2,1,3-benzoxadiazole (ABD-F) has been synthesized as a new fluorogenic reagent for thiols.Its reaction rate to homocysteine is over 30 times faster than that with ammonium 7-fluoro-2,1,3-benzoxadiazole-4-sulfonate (SBD-F).The fluorogenic reaction to thiol was completed quantitatively in 5 min at 50 deg C and pH 8.0.Alanine, proline, and cystine did not react under the same conditions.The fluorescence intensity of the fluorophor was pH dependent with the highest at pH 2.The ABD-thiols obtained by the prelabeling technique were separated and detected by reversed-phase HPLC.The detection limits (S/N = 3) for cysteine, glutathione, N-acetylcysteine, homocysteine, and cysteamine were 0.6, 0.4, 1.9, 0.5, and 0.5 pmol, respectively.