The biological activity of millimeter electromagnetic radiation (MEMR) has long been known that is the basis for its use in medicine. But the primary biophysical mechanisms of this factor at the molecular level remain poorly understood and debated. Because of it the features of the influence of microwave radiation on the optical properties of water solutions of hemoglobin with the aim to characterize the certain structural state of hemoglobin were investigated in this research. The object of the study was the optical properties of aqueous solutions of human hemoglobin in the concentration range of 7 and 15 ?M and in the temperature range 10–40°C. The optical spectra were recorded by using a BiospecMini (Shimadzu) spectrophotometer in the wavelength range of 190– 1100 nm. In order to increase the accuracy of the analysis of spectral data the spectra were normalized relative to the baseline which was taken as a line that ran parallel to the horizontal axis due to the minimum value of the optical density in the absorption spectrum. The values of the absorption maxima and the optical density were used as the main parameters of the absorption spectra. The B-spline function was used to more accurately determine these parameters. Microwave exposure of h&emoglobin solutions was performed at wavelength of 7,1 mm with power that calculated to be approximately 6mW. This power of electromagnetic radiation corresponds to the conditional limit range between thermal and non-thermal action of this factor. Th&e dependence of the optical properties of hemoglobin in the spectral range of heme absorption on temperature was analyzed and effects of microwave radiation on the optical properties of hemoglobin solutions were considered in frame of hypochromic eff&ects induced by temperature. It was revealed that the parameters of the absorption spectrum of an aqueous solution of hemoglobin depend on temperature. The optical density in the Sore band and the spectral bands of the oxygenated form of hemoglobin d&ecreases upon temperature increase. The observed temperature hypochromic effect is associated with increased protein aggregation. The effect of MEMR leads to a small but statistically significant hypochromism in the spectra of hemoglobin absorption t&hat testifies on increase in protein aggregation under the action of this physical factor which cause the changes in the hydration of protein molecules. This effect depends on the protein concentration and is not detected at low concentrations.
