Local environment perturbations in alpha1-antitrypsin monitored by a ratiometric fluorescent label.

The complex multistep inhibition of proteinases by alpha(1)-antitrypsin (alpha(1)-AT) was investigated by covalently labeling its unique Cys residue with a ratiometric environment-sensitive fluorescent dye, 6-bromomethyl-2-(2-furanyl)-3-hydroxychromone (BMFC). The binding of BMFC-labeled alpha(1)-AT with pancreatic elastase led to significant changes in the dual emission of BMFC. The 8 nm blue shift of one of the bands and ca.

Fluorescent derivatives of the GFP chromophore give a new insight into the GFP fluorescence process.

The photophysical properties of synthetic compounds derived from the imidazolidinone chromophore of the green fluorescent protein were determined. Various electron-withdrawing or electron-donating substituents were introduced to mimic the effect of the chromophore surroundings in the protein. The absorption and emission spectra as well as the fluorescence quantum yields in dioxane and glycerol were shown to be highly dependent on the electronic properties of the substituents.