[Change in conformation of proteins in aqueous solutions of heterofunctional nonelectrolytes].

In narrow ranges of concentrations of heterofunctional nonelectrolytes in aqueous solutions, structural transitions occur, which manifest themselves in the self-association of nonelectrolytes molecules and are accompanied by the screening of their hydrophobic groups from the contact with the solvent. In the same nonelectrolytes concentration ranges, conformational changes of protein molecules in solutions take place. The compatibility of the concentration ranges of these two processes is due to the fact that when nonelectrolytes molecules are extruded from the network of hydrogen bonds during the structural transition, both the self-association of nonelectrolytes molecules and their incorporation into the hydrate shell of the protein occur.

[Temperature changes of extracellular media state on a bacterial suspension].

Within temperature intervals 30-40 degrees C for bacterial suspension of E. coli and 24-34 degrees C for B. flavum the extracellular medium exists in a specific state.

[Changes in heat capacity upon protein denaturation].

By the use of infrared spectroscopy it has been shown that the configurational heat capacity of hydrogen bonds represents the principal contribution into the denaturational change of heat capacity of proteins.

[Thermostability of protein structure in the native state and mechanisms of its maintenance].

A comparison of temperature changes of the protein spectra with temperature behavior of other systems with hydrogen bonds shows high thermostability of the functional active structure of protein molecules. The stability of proteins space organization is regulated and supported by non-monotonous temperature changes of this organization. The physical mechanism of thermostabilization includes interaction of hydrophobic radicals of protein with the aqueous environment.

[Changes in the dehydrogenase activity of cardiomyocytes during acute experimental arterial occlusion of extremities].

The results of quantitative histoenzymologic investigations of succinate dehydrogenase, lactate dehydrogenase and NAD-diaphorase in cardiomyocytes of dogs with acute experimental arterial occlusion in ischemic and postischemic periods are reviewed. An increased activity of dehydrogenases in the early periods (3,6 h) of ischemia and during recirculation was established, with its noticeable reduction at later terms (9,12 h). Medical correction of postischemic disorders was shown to improve cardiomyocyte metabolism.

[Nonmonotonous character of temperature changes in protein conformation in predenaturational regions of temperatures].

Temperature changes of protein infrared spectra have a nonmonotonous pattern. On the curves of temperature relationships of spectral characteristics the regions of high frequency displacement have been observed, interrupted by sharp low frequency shifts, partly or entirely compensating the displacement of the bands in the preceding temperature interval. It has been shown that at temperatures corresponding to the high frequency displacement heat weakening of the strength of hydrogen bonds takes place.

[Quantitative histophotometric study of liver dehydrogenase activity during temporary ischemia of the extremities].

This prospective study depicts quantitative histophotometric characteristics of the changes in the histoenzymologic spectrum of the liver in the course of temporary ischemia of the extremities with subsequent revascularization. The increase in the activities of dehydrogenases under study in the course of a 3-hour ischemia, and the decrease of these parameters in 6- and 12-hour ischemia was discovered, that was determined as a compensatory response followed by the period of compensation exhaustion and the development of the period of complete exhaustion. The data of the study of drug correction of the postischemia syndrome confirmed the rationality of the efforts that were made.

[Spectroscopic study of conformational changes in proteins in aqueous solutions and mixed solvents].

The character of temperature changes of the absorption spectrum of water in protein solutions is the evidence of conformational changes of protein macromolecules. Along with the denaturation processes changes are also clearly seen at predenaturation stage. These changes involve a break of hydrophobic bonds in protein molecules and subsequent exponing of non-polar radicals into water.