| Abstrakt: |
A new derivatizing reagent, dansylaminomethylmaleic acid (DAM), was synthesized and utilized for the reversible fluorescence labeling of amino groups. The reagent DAM was dehydrated in the presence of (trimethylsilyl)ethoxyacetylene, a dehydrating agent, and the resulting anhydride reacted with amino groups, and could then be liberated under mild acidic conditions. With this reagent, benzylamine was derivatized as a model amino compound. The resultant fluorescent derivative, N-benzyl-2-dansylaminomethylmaleamic acid (BDAM), could be detected at 520 nm with fluorescence excitation at 340 nm. The fluorescence detection limit of BDAM (100 fmol, S/N=3) was smaller than that of intact benzyl-amine (200 pmol, S/N=10, absorbance at 254 nm). Under mild acidic conditions of pH 5.0, 82% of benzylamine was regenerated from BDAM within a day. With this reagent, insulin was successfully derivatized and 56% of insulin was regenerated. |
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