Y. Vladimirov - Academia.edu (original) (raw)

Papers by Y. Vladimirov

Research paper thumbnail of NO–hemoglobin may be a light-sensitive source of nitric oxide both in solution and in red blood cells

Journal of Photochemistry and Photobiology B: Biology, 2000

Hemoglobin in solution and inside red blood cells forms a complex with nitric oxide exhibiting a ... more Hemoglobin in solution and inside red blood cells forms a complex with nitric oxide exhibiting a specific EPR signal both at room and liquid nitrogen temperatures. In the present paper it was shown that the nitrosyl complex of hemoglobin (NO-Hb) is photochemically sensitive and hence may serve as a source of free NO under He-Cd laser irradiation (441 nm). It was found that at laser light radiant power of 3.9 mW, room temperature and in the presence of oxygen, 50% decrease of NO-Hb EPR signal occurred at doses of 54, 30, and 18 kJ/m2 for NO-hemoglobin solution, hemolysed and intact erythrocytes, respectively. The detection of free NO produced as a result of NO-Hb photolysis was performed by means of a spin trap, nitronyl nitroxyl radical NNR, which in the presence of NO is transformed into imino nitroxyl radical (INR) showing different EPR signal. In isolated hemoglobin solution, 20 mM INR was accumulated under irradiation with the maximal dose of 700 kJ/m2. In intact cells the HbFe(2+)-NO photolysis and NO release occur with essentially higher efficacy. To produce 100 mM INR, a dose of 290 kJ/m2 was needed in erythrocyte lysates and 100 kJ/m2 in intact red blood cell suspension. Measurements of absorption spectra showed that in all systems studied (NO-Hb in solution, intact erythrocytes and hemolysed erythrocytes) NO-Hb concentration decreased after irradiation by 14-22% with simultaneous formation of methemoglobin. These observations show that NO-Hb may serve as a store of nitric oxide from which free NO can be released by intensive illumination.

Research paper thumbnail of B9—Generation of hydroxyl radicals in the reaction of HOCl with Fe2+ ions: The interaction of hemoglobin with hypochlorite

Free Radical Biology and Medicine, 1994

10th Russian Seminar on Oxygen Radicals 13 ized zymosan (OZ), Phorbol myristate acetate (PMA), an... more 10th Russian Seminar on Oxygen Radicals 13 ized zymosan (OZ), Phorbol myristate acetate (PMA), and calcium ionophore A 23187. In order to measure the rate of oxygen radical production in cell suspensions, we use the chemiluminescence (CL) method with two CL amplifiers, luminol and lucigenin. DHLA was obtained daily by reducing LA with NABH 4.

Research paper thumbnail of B3—Influence of serum proteins on the fenton reaction: Chemiluminescence evidence

Free Radical Biology and Medicine, 1994

Research paper thumbnail of Evaluation of cytochrome c affinity to anionic phospholipids by means of surface plasmon resonance

Research paper thumbnail of Photobiological Principles of Therapeutic Applications of Laser Radiation

Biochemistry (Moscow), 2000

Research paper thumbnail of Generation of Free Radicals during Decomposition of Hydroperoxide in the Presence of Myeloperoxidase or Activated Neutrophils

Biochemistry (Moscow), 2005

It was shown with the spin trap alpha-(4-pyridyl-1-oxide)-N-tert-butylnitrone that myeloperoxidas... more It was shown with the spin trap alpha-(4-pyridyl-1-oxide)-N-tert-butylnitrone that myeloperoxidase (MPO) in the presence of its substrates H2O2 and Cl- as well as activated neutrophils destroy tert-butyl hydroperoxide producing two adducts of O-centered radicals which were identified as peroxyl and alcoxyl radicals. Inhibitory analysis performed with traps of hypochlorite (taurine and methionine), free radical scavengers (2,6-di-tret-butyl-4-methylphenol and mannitol), and MPO inhibitors (salicylhydroxamic acid and 4-aminobenzoic acid hydrazide) revealed that the destruction of the hydroperoxide group in the presence of isolated MPO or activated neutrophils was directly caused by the activity of MPO: some radical intermediates appeared as a result of the chlorination cycle of MPO at the stage of hypochlorite generation, whereas the other radicals were produced independently of hypochlorite, presumably with involvement of the peroxidase cycle of MPO. The data suggest that the activated neutrophils located in the inflammatory foci and secreting MPO into the extracellular space can convert hydroperoxides into free radicals initiating lipid peroxidation and other free radical reactions and, thus, promoting destruction of protein-lipid complexes (biological membranes, blood lipoproteins, etc.).

Research paper thumbnail of Cardiolipin activates cytochrome c peroxidase activity since it facilitates H2O2 access to heme

Biochemistry (Moscow), 2006

In this work, the effect of liposomes consisting of tetraoleyl cardiolipin and dioleyl phosphatid... more In this work, the effect of liposomes consisting of tetraoleyl cardiolipin and dioleyl phosphatidylcholine (1 : 1, mol/mol) on the rate of three more reactions of Cyt c heme with H2O2 was studied: (i) Cyt c (Fe2+) oxidation to Cyt c (Fe3+), (ii) Fe...S(Met80) bond breaking, and (iii) heme porphyrin ring decomposition. It was revealed that the rates of all those reactions increased greatly in the presence of liposomes containing cardiolipin and not of those consisting of only phosphatidylcholine, and approximately to the same extent as peroxidase activity. These data suggest that cardiolipin activates specifically Cyt c peroxidase activity not only because it promotes Fe...S(Met80) bond breaking but also facilitates H2O2 penetration to the reaction center.

Research paper thumbnail of Mechanism of activation of cytochrome c peroxidase activity by cardiolipin

Biochemistry (Moscow), 2006

In this work, the actions of bovine heart cardiolipin, synthetic tetraoleyl cardiolipin, and a no... more In this work, the actions of bovine heart cardiolipin, synthetic tetraoleyl cardiolipin, and a nonspecific anionic detergent sodium dodecyl sulfate (SDS) on cytochrome c (Cyt c) peroxidase activity recorded by chemiluminescence in the presence of luminol and on the Fe...S(Met80) bond whose presence was estimated by a weak absorption band amplitude with peak at 695-700 nm (A(695)) were compared. A strict concurrency between Fe...S(Met80) breaking (A(695)) and cytochrome peroxidase activity enhancement was shown to exist at cardiolipin/Cyt c and SDS/Cyt c molar ratios of 0 : 1 to 50 : 1 (by chemiluminescence). Nevertheless, when A(695) completely disappeared, Cyt c peroxidase activity under the action of cardiolipin was 20 times more than that under the action of SDS, and at low ligand/protein molar ratios (=4), SDS failed to activate peroxidase activity while cardiolipin enhanced Cyt c peroxidase activity 16-20-fold. A(695) did not change on Cyt c binding with liposomes consisting of tetraoleyl cardiolipin and phosphatidylcholine (1 : 10 : 10), while peroxidase activity was enhanced by a factor of 8. Breaking of 70% of the Fe...S(Met80) bonds resulted in only threefold enhancement of peroxidase activity. Cardiolipin-activated Cyt c peroxidase activity was reduced by high ionic strength solution (1 M KCl). The aggregated data suggest that cardiolipin activating action is caused, first, by a nonspecific effect of Fe...S(Met80) breaking as the result of conformational changes in the protein globule caused by the protein surface electrostatic recharging by an anionic amphiphilic molecule, and second, by a specific acceleration of the peroxidation reaction which is most likely due to enhanced heme accessibility for H(2)O(2) as a result of the hydrophobic interaction between cardiolipin and cytochrome.

Research paper thumbnail of Changes in Superoxide Dismutase Activity and Peroxynitrite Content in Rat Peritoneal Macrophages Exposed to He-Ne Laser Radiation

Biochemistry (Moscow), 2005

The formation of reactive oxygen and nitrogen species by rat peritoneal macrophages induced by a ... more The formation of reactive oxygen and nitrogen species by rat peritoneal macrophages induced by a low-intensity He-Ne laser radiation (LR) was studied in this work. It was found that the formation of reactive oxygen species, nitric oxide, and peroxynitrite as well as changes in the activity of superoxide dismutase (SOD) depended to a large extent on the LR dose. In particular, it was found that activation of SOD at low LR doses was accompanied by nitric oxide level increase, while the level of peroxynitrite showed no significant changes. On the other hand, an enhanced LR dose inhibited the enzyme, and this was accompanied by peroxynitrite accumulation. All the measurements were carried out the day after LR treatment. The revealed regularities consequently demonstrate the existence of a deferred LR action on macrophages associated with the production of reactive oxygen and nitrogen species.

Research paper thumbnail of NO–hemoglobin may be a light-sensitive source of nitric oxide both in solution and in red blood cells

Journal of Photochemistry and Photobiology B: Biology, 2000

Hemoglobin in solution and inside red blood cells forms a complex with nitric oxide exhibiting a ... more Hemoglobin in solution and inside red blood cells forms a complex with nitric oxide exhibiting a specific EPR signal both at room and liquid nitrogen temperatures. In the present paper it was shown that the nitrosyl complex of hemoglobin (NO-Hb) is photochemically sensitive and hence may serve as a source of free NO under He-Cd laser irradiation (441 nm). It was found that at laser light radiant power of 3.9 mW, room temperature and in the presence of oxygen, 50% decrease of NO-Hb EPR signal occurred at doses of 54, 30, and 18 kJ/m2 for NO-hemoglobin solution, hemolysed and intact erythrocytes, respectively. The detection of free NO produced as a result of NO-Hb photolysis was performed by means of a spin trap, nitronyl nitroxyl radical NNR, which in the presence of NO is transformed into imino nitroxyl radical (INR) showing different EPR signal. In isolated hemoglobin solution, 20 mM INR was accumulated under irradiation with the maximal dose of 700 kJ/m2. In intact cells the HbFe(2+)-NO photolysis and NO release occur with essentially higher efficacy. To produce 100 mM INR, a dose of 290 kJ/m2 was needed in erythrocyte lysates and 100 kJ/m2 in intact red blood cell suspension. Measurements of absorption spectra showed that in all systems studied (NO-Hb in solution, intact erythrocytes and hemolysed erythrocytes) NO-Hb concentration decreased after irradiation by 14-22% with simultaneous formation of methemoglobin. These observations show that NO-Hb may serve as a store of nitric oxide from which free NO can be released by intensive illumination.

Research paper thumbnail of B9—Generation of hydroxyl radicals in the reaction of HOCl with Fe2+ ions: The interaction of hemoglobin with hypochlorite

Free Radical Biology and Medicine, 1994

10th Russian Seminar on Oxygen Radicals 13 ized zymosan (OZ), Phorbol myristate acetate (PMA), an... more 10th Russian Seminar on Oxygen Radicals 13 ized zymosan (OZ), Phorbol myristate acetate (PMA), and calcium ionophore A 23187. In order to measure the rate of oxygen radical production in cell suspensions, we use the chemiluminescence (CL) method with two CL amplifiers, luminol and lucigenin. DHLA was obtained daily by reducing LA with NABH 4.

Research paper thumbnail of B3—Influence of serum proteins on the fenton reaction: Chemiluminescence evidence

Free Radical Biology and Medicine, 1994

Research paper thumbnail of Evaluation of cytochrome c affinity to anionic phospholipids by means of surface plasmon resonance

Research paper thumbnail of Photobiological Principles of Therapeutic Applications of Laser Radiation

Biochemistry (Moscow), 2000

Research paper thumbnail of Generation of Free Radicals during Decomposition of Hydroperoxide in the Presence of Myeloperoxidase or Activated Neutrophils

Biochemistry (Moscow), 2005

It was shown with the spin trap alpha-(4-pyridyl-1-oxide)-N-tert-butylnitrone that myeloperoxidas... more It was shown with the spin trap alpha-(4-pyridyl-1-oxide)-N-tert-butylnitrone that myeloperoxidase (MPO) in the presence of its substrates H2O2 and Cl- as well as activated neutrophils destroy tert-butyl hydroperoxide producing two adducts of O-centered radicals which were identified as peroxyl and alcoxyl radicals. Inhibitory analysis performed with traps of hypochlorite (taurine and methionine), free radical scavengers (2,6-di-tret-butyl-4-methylphenol and mannitol), and MPO inhibitors (salicylhydroxamic acid and 4-aminobenzoic acid hydrazide) revealed that the destruction of the hydroperoxide group in the presence of isolated MPO or activated neutrophils was directly caused by the activity of MPO: some radical intermediates appeared as a result of the chlorination cycle of MPO at the stage of hypochlorite generation, whereas the other radicals were produced independently of hypochlorite, presumably with involvement of the peroxidase cycle of MPO. The data suggest that the activated neutrophils located in the inflammatory foci and secreting MPO into the extracellular space can convert hydroperoxides into free radicals initiating lipid peroxidation and other free radical reactions and, thus, promoting destruction of protein-lipid complexes (biological membranes, blood lipoproteins, etc.).

Research paper thumbnail of Cardiolipin activates cytochrome c peroxidase activity since it facilitates H2O2 access to heme

Biochemistry (Moscow), 2006

In this work, the effect of liposomes consisting of tetraoleyl cardiolipin and dioleyl phosphatid... more In this work, the effect of liposomes consisting of tetraoleyl cardiolipin and dioleyl phosphatidylcholine (1 : 1, mol/mol) on the rate of three more reactions of Cyt c heme with H2O2 was studied: (i) Cyt c (Fe2+) oxidation to Cyt c (Fe3+), (ii) Fe...S(Met80) bond breaking, and (iii) heme porphyrin ring decomposition. It was revealed that the rates of all those reactions increased greatly in the presence of liposomes containing cardiolipin and not of those consisting of only phosphatidylcholine, and approximately to the same extent as peroxidase activity. These data suggest that cardiolipin activates specifically Cyt c peroxidase activity not only because it promotes Fe...S(Met80) bond breaking but also facilitates H2O2 penetration to the reaction center.

Research paper thumbnail of Mechanism of activation of cytochrome c peroxidase activity by cardiolipin

Biochemistry (Moscow), 2006

In this work, the actions of bovine heart cardiolipin, synthetic tetraoleyl cardiolipin, and a no... more In this work, the actions of bovine heart cardiolipin, synthetic tetraoleyl cardiolipin, and a nonspecific anionic detergent sodium dodecyl sulfate (SDS) on cytochrome c (Cyt c) peroxidase activity recorded by chemiluminescence in the presence of luminol and on the Fe...S(Met80) bond whose presence was estimated by a weak absorption band amplitude with peak at 695-700 nm (A(695)) were compared. A strict concurrency between Fe...S(Met80) breaking (A(695)) and cytochrome peroxidase activity enhancement was shown to exist at cardiolipin/Cyt c and SDS/Cyt c molar ratios of 0 : 1 to 50 : 1 (by chemiluminescence). Nevertheless, when A(695) completely disappeared, Cyt c peroxidase activity under the action of cardiolipin was 20 times more than that under the action of SDS, and at low ligand/protein molar ratios (=4), SDS failed to activate peroxidase activity while cardiolipin enhanced Cyt c peroxidase activity 16-20-fold. A(695) did not change on Cyt c binding with liposomes consisting of tetraoleyl cardiolipin and phosphatidylcholine (1 : 10 : 10), while peroxidase activity was enhanced by a factor of 8. Breaking of 70% of the Fe...S(Met80) bonds resulted in only threefold enhancement of peroxidase activity. Cardiolipin-activated Cyt c peroxidase activity was reduced by high ionic strength solution (1 M KCl). The aggregated data suggest that cardiolipin activating action is caused, first, by a nonspecific effect of Fe...S(Met80) breaking as the result of conformational changes in the protein globule caused by the protein surface electrostatic recharging by an anionic amphiphilic molecule, and second, by a specific acceleration of the peroxidation reaction which is most likely due to enhanced heme accessibility for H(2)O(2) as a result of the hydrophobic interaction between cardiolipin and cytochrome.

Research paper thumbnail of Changes in Superoxide Dismutase Activity and Peroxynitrite Content in Rat Peritoneal Macrophages Exposed to He-Ne Laser Radiation

Biochemistry (Moscow), 2005

The formation of reactive oxygen and nitrogen species by rat peritoneal macrophages induced by a ... more The formation of reactive oxygen and nitrogen species by rat peritoneal macrophages induced by a low-intensity He-Ne laser radiation (LR) was studied in this work. It was found that the formation of reactive oxygen species, nitric oxide, and peroxynitrite as well as changes in the activity of superoxide dismutase (SOD) depended to a large extent on the LR dose. In particular, it was found that activation of SOD at low LR doses was accompanied by nitric oxide level increase, while the level of peroxynitrite showed no significant changes. On the other hand, an enhanced LR dose inhibited the enzyme, and this was accompanied by peroxynitrite accumulation. All the measurements were carried out the day after LR treatment. The revealed regularities consequently demonstrate the existence of a deferred LR action on macrophages associated with the production of reactive oxygen and nitrogen species.