[Mechanism of quenching of hematoporphyrin and mono-L-aspartyl chlorine e6 triplet states by metronidazole].

The quenching of the triplet state of hematopophyrin (3HP.) and mono-L-aspartyl chlorine e6, (3MACE.) by metrotlidazole (METRO) ground state, has been investigated in binary mixtures of water and aliphatic alcohol by means of 532 nm laser flash.

[The role of conformational mobility in the decay of free-radical states in proteins].

The kinetic study of decay reaction of macroradicals in proteins with the use of a stochastic dynamic model of proteins has been carried out. Two types of distributions of the effective coefficients (diffusion, friction and viscosity) corresponding to two types of conformational motion of proteins have been obtained. The distributions of the effective parameters corresponding to the diffusion of protein molecule over conformational states are equal for all.

[Decarboxylation of amino acids and peptides in a photoreaction with potassium ferricyanide at 77 K].

We have measured action spectra of formation of radicals in aliphatic amino acids and peptides by reaction of decarboxylation with excited potassium ferricyanide. Peptides are capable to the reaction under longwave absorbtion band excitation, whereas amino acids are stable under these conditions, and decarboxylation occur only under irradiations by lambda < 400 nm.

[The effect of water and secondary structure on the thermal stability of macroradicals in proteins].

The thermostability of macroradicals located in the protein peptide chain segments with the different secondary structure was investigated. It has been shown at the dry proteins that just the secondary structure determines the thermostability of the macroradicals. In the different proteins the thermostability of macroradicals in peptide chain segments with identical secondary structure is the same.

[Population of triplet-excited states of tryptophanyls and tyrosyls in proteins].

The relative limiting concentrations of triplet excited states of tryptophan and tyrosine residues have been measured by the ESR method. The magnitude of limiting concentration of the tryptophan and tyrosine residues T1-states does not vary to fit their numbers in some proteins. A limitation on the concentration of T1-states is accounted for by the fact that in protein molecules there occurs the radiationless excitation energy transfer of chromophores on residues in the triplet state.

[Study of free radical reactions in proteins by a recombination-kinetic method].

In terms of the polychronous kinetics model there were obtained values of efficient activation energy (Eeff) for a slow reaction of the death of free macroradicals in UV-irradiated at 77K silk fibroin and tendons with 80 and 15% humidity. In silk fibroin Eeff equals 6 +/- 1 kkal.mole-1 at 313-413 K and 14 +/- 1 kkal.

[Mechanisms of death of free radical states in proteins].

Mechanism of the death of free radicals formed under the effect of different destructing factors in proteins without a prosthetic group is considered. The death of macroradicals in proteins is suggested to be due to a recombination of free radical states of aromatic amino acid residues and atom hydrogen braking away as a result of transformation of the middle radicals -NH-C alpha R-CO- from the nearest NH-group. Possible way of middle radicals transformation is proposed which leads to the breakage of hydrogen.

[Study of soluble proteins of mouse crystalline lenses (normal and in cataract)].

The water-soluble proteins from mice lenses (normal and cataract lenses) were investigated by methods of absorption spectrophotometry and kinetics of UV-induced radical decay. General characteristic of internal structure of extraction proteins was investigated by recombination kinetic method. It was shown that concentration of water-soluble proteins lowered ten times in lenses of mature cataract, i.

[Supernarrow EPR spectrum of aqueous protein solutions, UV-irradiated at 77 K].

The nature was studied of paramagnetic centres photoinduced in aqueous solutions of proteins, amino acids and peptides at 77 K, having a supernarrow ESR spectrum with the width 8 mkTl and g = 1.9988 +/- 0.0002.

[The effect of the charge of aromatic amino acid, peptide and protein molecules on the rate of radical formation during UV-irradiation].

It has been shown that the rate of radical formation under UV-irradiation of some aromatic amino acids, peptides and proteins abruptly increases with pH rise in the region 9.5-11. This effect is observed only in the case when the total charge of the molecule after ionization remains negative.

[Accumulation of UV-induced radicals in proteins with various degree of aggregation].

Accumulation of radicals UV-induced in protein solutions at 77 K was investigated. It has been found that in each molecule of small proteins true solutions only one ionization proceeds and two radicals are formed. The limiting number of radicals per one protein molecule decreases with the increase of their aggregation level.

[Relative size of collagen body-peptides of the human cornea in the normal state and in keratoconus].

Recombination-kinetic study was carried out of the ratio between collagen secondary structures in human eye cornea of different age in the norm and in keratoconus. It has been shown that in both normal and pathologically changed cornea the portion of peptide chain in telopeptides is not changed within the age interval studied.

[The size of non-helical regions in collagen I from the skin of cold-blooded animals].

The portion of non-spiralized peptide chain in collagen 1 molecules from the skin of cold-blooded animals, such as Arenicola marina, Gadus morhua marisalbi, Eleginus navaga, Rana amurensis, Rana temporaria, Rana semiplicata, Rana ridibunda, Rana dolmatina, Rana graeca, Bombina variegata was determined by recombination-kinetic method. It has been shown that the portion of non-spirilized part of collagen I molecule changes in the animals studied from 2 to 11% and correlates with the temperature of their habitat. There exist also substantial interspecies differences in the collagen I molecule structure.

[The study of photo-induced rhodopsin aggregation in the photoreceptor membrane by electron paramagnetic resonance].

The ESR measuring of UV-induced free radicals concentration limit has been used for studying rhodopsin aggregate state in the photoreceptor membrane.

[Effect of water on the thermostability of free radicals in tendon collagen].

Recombination-kinetic method was applied for studying collagen of rat tail tendons. Annealing of UV-induced free radicals in tendons of various humidity was investigated.

[Determination of the degree of collagen coiling by electron paramagnetic resonance].

It has been shown that kinetics of the death of free radicals UV-induced at 77 degrees K in collagen is determined by two reactions having different rates. Such shape of the kinetic curve is substantiated by the spatial structure of macromolecules and permits to find easily the portion of peptide chains in the helical form and the portion of end peptides not incorporated in this structure. The degree of helical pattern of collagen from rat skin was shown to be 92%.

[Effect of luminescence quenchers on the maximum concentration of radicals in proteins following UV-irradiation (77 K)].

It has been shown that the limiting number of ionization acts (z) in a protein molecule in water solution UV-irradiated at 77 K is in proportion to the molecular weight: z=8.10(-6) M. Only one ionization is possible in simple protein with M=12,5.

[Luminescence quenching of UV-irradiated proteins].

Kinetic curves of paramagnetic centres accumulation and quenching of the luminescence of UV-irradiated proteins at 77 degrees K are compared. Initiation of luminescence of UV-irradiated proteins at the annealing of paramagnetic centres was studied. The luminescence of UV-irradiated proteins was shown to be quenched with the paramagnetic centres formed.

[Kinetic equation for the process of accumulation of paramagnetic centers in proteins exposed to UV-radiation].

The process of accumulation of paramagnetic centres in UV-irradiated solutions of simple proteins at 77 degrees K has been studied. A kinetic equation describing the accumulation of radicals in protein is obtained. Experimentally obtained curves of radical accumulation coincide with the theoretical ones.

[Accumulation of paramagnetic centers in protein solutions exposed to UV-radiation].

It is shown that concentration of paramagnetic centres (PC) in UV-irradiated protein solutions at 77degreesK approximates the limiting value. The limiting number of PC (n) per one molecule is in direct proportion to that of aromatic amino acid residues in it n(sigma)=2+0,1 sigma. The formation of PC slopps because all the energy absorbed by aromatic amino acid residues is transfered to the radicals formed.

[Mechanism of the formation of paramagnetic centers in proteins exposed to UV-radiation].

It is shown that the process of formation of paramagnetic centres in UV-irradiated at 77degreesK protein solutions in a biquantum one. The protein molecule in triplet state is an intermediate product.