Phase-fluorimetry study on dielectric relaxation of human serum albumin.

The dielectric relaxation (DR) of human serum albumin (HSA) was studied by the method of phase-fluorometry. The protein environment of the single tryptophan in HSA shows a relatively low-speed DR of sub-ns characteristic time. This relaxation can be measured as a decaying red-shift of the time-resolved fluorescence emission spectra. The details of calculations of time-emission matrices (TEM) and comparison to the fluorescence data of the reference solution of N-acetyl-L-tryptophanamide (NATA) are also presented.