Fluorescence Spectroscopy of N-acetyl-L-tryptophan-amide and Proteins under High Pressure: Effects of Pressure, Temperature, and Organic Additives

摘要

The fluorescence of N-acetyl-L-tryptophanamide and proteins was measured and quantified by the center of the spectral mass, <ν>. When a protein was excited at 295 nm, the fluorescence of tyrosine was negligible and the fluorescence of only tryptophanwas obtained and reflected in the <ν> The <ν> changed depending on the nature of the solvent used, as well as the temperature, and pressure, and was linearly correlated with the dielectric constant of the solvent. When several proteins were denaturedin 8 M urea containing 0.1 M DTT, the <ν> yielded a constant value at 27,750±54 cm~(-1), except Ac-Trp-NH_2, Ac-Trp-(Glu)_(120), and V124W RNase A, where the <ν> was slightly smaller than that of the denatured proteins. Thus, the <ν> of protein fluorescence, excited at 295 nm, is a useful value in evaluating the extent of protein folding and unfolding.