Reaction of Fluorescein-isothiocyanate with Proteins and Amino Acids

Part III. Syntheses of Trifluoroacetic Acid Salts of Fluoresceinthiohydantoin Amino Acids and their Spectrometric Studies

Abstract

The structure of fluorescein chromophore was studied with infrared and nuclear magnetic resonance spectrometries. Fluorescein chromophore formed acid salt with strong acid and this salt was decomposed with water.
Fluorescein derivatives were allowed to crystallize into trifluoroacetic acid salts. The new compounds, trifluoroacetic acid salts of fluorescein thiohydantoin (FTH)^* amino acids, were synthesized and they were studied with ultraviolet, visible, fluorescence and infrared spectrometries, as well as optical rotatory dispersion and nuclear magnetic resonance.
The trifluoroacetic acid salts of FTH-amino acids were superior to trifluoroacetic acid-free form as the standard materials of N-terminal analysis.