[Glycine receptors in nervous tissue and their functional role].

The literature data on glycine metabolism in neural tissue, mitochondrial Gly-cleaving system, Gly-catching system in neural and glial cells are summarized. The peculiarities of localization and distribution of specific glycine receptors and binding-sites in nervous tissue of mammals are described. Four types of glycine-binding receptors are described: own specific glycine receptor (Gly-R), ionotropic receptor, which binds N-methyl-D-aspartate selectively (NMDA-R), and ionotropic receptors of g-aminobutyrate (GABA A -R, GABA С -R).

TiO2 nanoparticles suppress Escherichia coli cell division in the absence of UV irradiation in acidic conditions.

TiO(2) nanoparticles (NPs) activated by UV irradiation are known to have a bactericidal effect. In this study we report the details of TiO(2) NPs influence on the colony-forming capacity of E. coli in the dark at pH 4.

[Contribution of blue-green pigments to hemolytic activity of Pseudomonas aeruginosa cultural fluid].

Aim: To assess the contribution of blue-green pigments of Pseudomonas aeruginosa to hemolytic activity of its cultural fluid. MATERIALS AND METHODS. Eight hospital strains and reference strain ATCC 15442 were used.

[Effects of biogenic phosphates on protease-induced protein cleavage and functioning of plasminogen activators].

We showed, using the method of lysis of fibrin plates and five substrate proteins in a thin layer of agar gel, that inorganic orthophosphate (0.001-0.06 M) enhances by 50-250% the activatory functions of streptokinase, urokinase, and tissue plasminogen activator and, in general, by 1.

[Effects of plasminogen and streptokinase on the vital functions of nervous tissue cells in culture].

In the protein-deficient media plasminogen stimulated the vital functions of cells and in concentrations 10(-7)-10(-10) M it protected cells of sympathetic ganglia, neocortex and continues cell lines under damaging actions of H2O2 (0.0001 M), NH4CI (0.01 M) and cooling.

[Effects of plasminogen, streptokinase and their equimolar complexes with pyruvate kinase on the human neuroblastoma IMR-32 cells].

The system of extracellular proteolysing, consists of plasminogen (PGn), its active protease (plasmin), PGn activation and PGn activators inhibitors, influences the nervous tissue functions, their growth, differentiation and proliferation in both, normal and pathological conditions. The purpose of the investigation was to study the effects of exogenous PGn, its activator streptokinase (SK), PK and their equimolar complex on the morpho-functional state neuroblastoma IMR-32 cells. PGn, SK, PK and their complexes stimulated cells proliferation during 1-3 days of incubation, shown by cell quantity increase.

Some unusual manifestations of proteolysis.

In the article the results of the long-term researches revealing the essence of the following three phenomena are generalized. 1. Participation of active oxygen species (especially, superoxide radical) in activation of zymogens--plasminogen, trypsinogen, chymotrypsinogen, pepsinogen and in realization of the catalytic (proteolytic) function of a number of proteinases.

Effects of streptokinase on the development of rat cerebral cortical cells in vitro.

The aim of the present work was to study the effects of streptokinase (SK) on the ultrastructure of the cellular elements of the cerebral cortex of neonatal rats in vitro. Three series of cultures were used: cultures maintained in DMEM enriched with 15% fetal calf serum (control 1), some transferred to minimal nutritive medium containing only 0.5% serum (control 2), and some supplemented with SK (2000 MU/ml) (experimental).

[The effect of streptokinase on the development of rat cerebral cortex cells in vitro].

The aim of this study was to determine the effect of streptokinase (SK) on the ultrastructure of cellular elements in the cerebral cortex of newborn rats in vitro. Three series of cell cultures grown on DMEM were used, including those grown on the medium enriched with 15% fetal calf serum (control 1), cultures transferred to the depleted medium containing only 0.5% of this serum (control 2), and the experimental cultures, to which SK (2000 IU/ml) was added.

[Synthesis of modified fragments of fibrinogen and their effect on the activity of proteolytic enzymes].

New analogues of the Gly-Pro-Arg and Arg-Gly-Asp fragments of fibrinogen were synthesized: Gly-Pro-Arg-Pro (I), Gly-Pro-Arg-Pro-Met-OMe (II), Gly-Pro-Arg-Pro-Phe (III), Gly-Pro-Arg-Pro-Asp (IV), Gly-Pro-Arg-Pro-Glu (V), and Arg-Asn-Trp-Asp (VI). Their effect on the activity of proteases of various types was studied with the method of lysis of fibrin plates. All the peptides were found to inhibit plasmin activity (by 60-85%) and the gamma-subunit of nerve growth factor (by 55-93%).

Enzymatic oxidation of cadmium and lead metals photodeposited on cadmium sulfide.

Cadmium and lead metals deposited on CdS particles are shown to act as substrates--electron donors for enzymes, hydrogenase from Thiocapsa roseopersicina (HG), NAD-dependent hydrogenase from Alcaligenes eutrophus (NLH), and ferredoxin:NADP oxidoreductase (FNR) from Chlorella in the formation of hydrogen, NADH and NADPH, respectively. Adsorption of the enzyme on the surface of the metallized CdS particle is required for enzymatic oxidation of metal. The maximum rates for the formation of hydrogen and NADH catalyzed by hydrogenase and NAD-dependent hydrogenase with metals as electron donors are comparable with the rates obtained for these enzymes using soluble substrates.

Inorganic semiconductors as photosensitizers in biochemical redox reactions.

The results of studies of biochemical redox reactions photosensitized by inorganic semiconductor particles are reviewed. The mechanisms of hydrogen photoproduction, NAD+ or NADP+ photoreduction, CO2 photofixation and photosynthesis of organic and amino acids under the coupled action of TiO2, ZnO, CdS, ZnS and enzymes or bacterial cells are considered. Studies on the photocatalytic activity of ferritin, a protein containing microcrystals of hydrous ferric oxide, are described.

Light induced redox reactions involving mammalian ferritin as photocatalyst.

Under excitation by visible light the iron storage protein ferritin catalyses the reduction of cytochrome c and viologens as well as the oxidation of carboxylic acids, thiol compounds, and sulfite. The photochemically active element of ferritin is its mineral ferrihydrite semiconductor core. Band-gap excitation of these microcrystals leads to generation of electron-hole pairs that are sufficiently long-lived and reactive to engage in redox reactions with components of the medium.

Effect of active oxygen species scavengers on fibrinolytic activity of some proteinases.

Scavengers of different active oxygen species affect fibrin plate lysis, catalysed by various proteinases, only at relatively high concentrations (> 10(-2) M). Singlet oxygen scavengers change proteinase activity insignificantly except for strong inhibition of pepsin and papain by sodium azide, but pepsin-by histidine, and fibrinolytic urokinase activity-by all used O2 delta 1 scavengers. Of all used scavengers of OH-radical only ethanol caused significant changes in the proteinases under study, except for alpha-chymotrypsin.

The state of tryptophan-containing sites of human, bovine and rabbit plasminogens with changing solution pHs.

The state of tryptophan-containing sites is proved to be stable by intrinsic tryptophan fluorescence with pH 5-8, 7-9, and 6-9 in human, rabbit and bovine plasminogen molecules, respectively. With pH < 5.0 tryptophan-containing sites of human zymogen (in contrast to rabbit and bovine ones) undergo conformational transitions.

[Structural organization of the streptokinase molecule].

Conformational changes of the tryptophan-containing sites of streptokinase, its secondary and tertiary structures under the effect of NaCl, urea, heating, pH solution shift were analysed. Data on the reversibility of streptokinase's conformational changes, the flexibility of its structure, the presence of domains in the molecule were considered.

Metal as a novel type of the enzyme substrate. Metallic cadmium photogenerated in the system CdS-formate as a substrate of the NAD-dependent hydrogenase.

The process of NAD+ photoreduction under the coupled action of CdS semiconductor and NAD-dependent hydrogenase from hydrogen-oxidizing bacterium Alcaligenes eutrophus may be divided into light and dark stages. At the first stage, illumination of the system leads to the photooxidation of the sacrificial electron donor and results in the reduction of the semiconductor surface. At the second dark stage NAD+ is reduced to NADH in the presence of hydrogenase.

[Mechanism of the cytologic action of streptolysin O: effect of scavengers of active oxygen species and complexons on erythrocyte hemolysis].

The hemolysis of rabbit erythrocytes, initiated by streptolysin O purified samples, is appreciably suppressed in the presence of the scavengers of singlet oxygen (sodium azide, histidine, tryptophan), .OH-radical (ethanol, mannitol), O.(2-)-radical (nitrotetrazolium blue, streptokinase), chelating agents (o-phenanthroline, sodium diethyldithiocarbamate) and some oxidoreductants such as K3FeCN6 and riboflavin as well.

Conformation ability test of human, rabbit and bovine plasminogens and their specific interaction with streptokinase.

Human, rabbit and bovine plasminogens, having different sensitivity to streptokinase-activating action, differ, according to spectrophotometric titration, tryptophan fluorescence and circular dichroism spectroscopy, in the state of tyrosine and tryptophan residues, and in secondary and tertiary structures. Human plasminogen-streptokinase equimolar complex formation (according to gel chromatography) is accompanied by a differential ultraviolet spectrum. Difference spectroscopy is a convenient and adequate means of studying the formation of the said complexes.

Photogeneration of NADH under coupled action of CdS semiconductor and hydrogenase from Alcaligenes eutrophus without exogenous mediators.

Photoreduction of NAD has been accomplished by a system consisting of the NAD-dependent hydrogenase from Alcaligenes eutrophus immobilized on CdS particles with formate as artificial electron donor. Enzymatically active NADH is formed under illumination of this system by visible light. Accumulation of the coenzyme dimer (NAD)2 was not detected.

[Physico-chemical properties of the thrombolytic compound longolytin].

A preparation exhibiting high fibrinolytic activity and ability to activate plasminogen was isolated from cultivation medium of Arthrobotrys longa. Homogeneous protein, obtained after gel filtration on Sephadex G-100, had molecular mass 28,600, pI-3.68-3.

On the plasminogen-activating function of streptokinase.

1. Several hypotheses have been advanced to explain the activating function of streptokinase. The predominant hypothesis suggests a stable equimolar streptokinase-plasmin(ogen) complex, activating free plasminogen by an active centre, which is located in the plasmin(ogen) part of the complex.

[Chemical modification of the functional groups of streptokinase B in the water-soluble carbodiimide-nucleophile system].

Specific activity of streptokinase was decreased after incubation in the system containing I-ethyl-3(3-dimethyl aminopropyl) carbodiimide (EDC)--ethylene diamine. Under these conditions about 8 free amino groups and 38 free carboxylic groups were modified in the streptokinase molecule. The protein conformation and the state of tryptophane residues were altered.

[Modification of functional groups of the streptokinase molecule during photooxidation].

Photochemical oxidation with methylene blue as photosensitizer results in the destruction of one histidine residue in the streptokinase molecule. This process is characterized by the rate constant corresponding to the modification of free L-histidine and results in partial inactivation of the protein. The rate of protein photo oxidation and photoinactivation is pH-dependent.