APPLICABILITY OF PHOTOFLUORESCENT TECHNIQUES FOR RESEARCH OF PROTEIN STRUCTURE DYNAMICS IN AQUEOUS SOLUTIONS

Abstract

Subject of research. This paper presents developed techniques for research of the spatial structure changes of protein molecules when the state of these molecules is close enough to that one in living organisms, actively participating, as enzymes, in regulating the metabolism of the latter. Method. The synchronous photofluorescence spectra of aqueous solutions of casein milk protein were studied in the visible and near ultraviolet regions at different shifts of emission wavelengths relative to excitation wavelength (D_wl). Main results. Significant differences were observed both in the intensity and in the position of light scattering peaks and the own molecular photofluorescence of casein water solutions not only at different concentrations of the protein component in them, but also depending on the duration of casein presence in a dissolved state. Apparently, this fact was due to the differences in the spatial structure of protein molecules in the studied solutions (determined, in turn, by different degrees of hydrogen and Van der Waals interactions of these high-molecular compounds together with the water molecules surrounding them). Practical relevance. It was demonstrated that photoluminescence techniques provide the researcher with a fairly simple, reliable and informative way of studying both thermodynamic and kinetic aspects of the interaction of protein molecules, which are in a state close to the native, with the surrounding molecules of the other substances (including water). The synchronous spectra of the intrinsic molecular photofluorescence of aqueous protein solutions can be used for this, which are recorded at D_wl = 10 nm in the excitation wavelength range from 230 to 600 nm. Whereas similar spectra recorded at D_wl = 0 and 90 nm can be recommended for more sensitive quantitative determination of the protein content in aqueous solutions.