Phenylalanine Dielectric constant
Springer Online Journal Archives 1860-2000
Abstract A tunable fourth derivative UV absorbance method based on a variable spectral shift has been developed and compared to the Savitzky-Golay method and the analytical derivative. The parameters of the method were optimised for the analysis of the UV absorbance spectra of the aromatic amino acids to quantify the effect of decreasing solvent polarity on their fourth derivative spectra. The wavelength of the highest maximum (λmax) (for tyrosine and phenylalanine) or the amplitude of the highest maximum (Amax) (for tryptophan), were shown to depend linearly on the dielectric constant of the solvent, ranging from water to cyclohexane. The only effect of pressure in the 1 to 500 MPa range is a small decrease in the fourth derivative amplitude. This method appears therefore as a suitable tool to evaluate changes of the dielectric constant in the vicinity of the aromatic amino acids in proteins which undergo pressure induced structural changes.
Type of Medium: