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V Z Gorkin

Publications and source records attributed to V Z Gorkin.

At least 19 recordsLinked to original sources
PubMed1992

Increase of brain endogenous monoamine oxidase inhibitory activity (tribulin) in experimental audiogenic seizures in rats: evidence for a monoamine oxidase A inhibiting component of tribulin.

Brain tribulin activity in rats with an inherited predisposition to audiogenic epilepsy was studied after seizures of different intensity were induced by an electric bell. Weak seizures (from 0 to 2 arbitrary units) did not produce any changes in endogenous inhibitory activity towards either monoamine oxidase (MAO) A or B. Moderate seizures were characterized by increases in both MAO A and MAO B inhibitory activity (up to 1.9-fold). Complete tonic epileptiform seizures with total areflexia (4 arbitrary units) induced further augmentation (up to 2.5-fold) of MAO A but not of MAO B inhibitory activity. This dissociation between the two inhibitory activities points to the existence of a separate MAO A-inhibiting component of brain tribulin which is different from isatin.

Animals↗
PubMed1979

On preparative separation of brain mitochondrial monoamine oxidases.

A method was developed for solubilization from bovine brain stem mitochondrial fraction of monoamine oxidases deminating biogenic amines. Preparative separation of the monoamine oxidases, possessing different substrate specificities, was achieved by column chromatography on a biospecific adsorbent AH-Sepharose 4 B. The enzyme preparations thus obtained did not contain any detectable by disc-electrophoresis of isoelectrofocusing in polyacrylamide gels proteins which were devoid of the monoamine oxidase activity.

Animals↗
PubMed1979

[Kinetic patterns of their reactions catalyzed by membrane-bound monoamine oxidase].

The initial rate (v) versus initial substrate concentration [S]0 plots for the reaction of serotonin deamination catalyzed by rat liver mitochondrial monoamine oxidase are characterized by complicated non-hyperbolic patterns. The shapes of the curves in the plots depend on the age and strain of the animals used or on alterations in the physico-chemical state of mitochondria caused by freezing -- thawing and swelling in hypotonic solutions. The v versus [S]0 plots for other substrates (e. g. tyramine) do not obey the Michaelis -- Menten equation as well. In order to interpret the kinetic patterns described a model of the mitochondrial monoamine oxidase structure and function has been proposed. The model is based on the assumption that both catalytic and regulatory allosteric sites are present on the surface of monoamine oxidase molecules. In the process of serotonin or tyramine binding the monoamine oxidases exhibit cooperative properties which are characteristic for the allosteric enzymes. The model also suggests an active regulatory role of the mitochondrial membrane itself.

Animals↗
PubMed1978

[Multiplicity of monoamine oxidase: inhibition of mitochondrial monoamine oxidase activity by isopropylhydrazide of D,L-serine].

Isopropylhydrazide of D,L-serine (IHS) inhibits by 50% (at 37 degrees for 10 min) deamination of serotonin or beta-phenylethylamine by monoamine oxidases from bovine brain stem mitochondrial membranes at the 2.6 X X 10(-5) M or 9 X 10(-5) M, respectively. In order to inhibit by 50% the deamination of tyramine under the same conditions a considerably lower (2.5 X X 10(-6) M) concentration of IHS is required. Kinetic studies of inhibition of enzymatic deamination of all the three biogenic monoamines by IHS showed that the irreversible blocking of the monoamine oxidase activity is preceeded by formation of dissociating enzyme-inhibitor complexes. Values of the dissociation constants of these complexes measured (at 37 degrees) with serotonin, phenylethylamine or tyramine as substrates for estimation of the residual monoamine oxidase activity are 0.47; 0.13 or 0.023 mM, respectively. Significant differences are also found between thermodynamic and activation parameters characterizing both both steps of interaction between IHS and the monoamine oxidases of mitochondrial membranes in the experiments with serotonin, phenylethylamine or tyramine as substrates. The data obtained suggest the existence of different monoamine oxidases (or their active sites) catalyzing oxidative deamination of serotonin, phenylethylamine or tyramine in the fragments of mitochondrial membranes from bovine brain stem.

Animals↗
PubMed1977

[Monoamine oxidase type B and the function of Ca2+, Mg2+-dependent adenosine triphosphatase of preparations of sarcoplasmic reticulum vesicles].

Oxidative deamination by monoamine oxidases of B type in the preparations of sarcoplasmic reticulum vesicles from rabbit skeletal muscles of beta-phenylethylamine or benzylamine was accompanied by a decrease of both the active transport of Ca2+ into the vesicles and Ca2+, Mg2+-dependent ATP-ase activity. This decrease was prevented by pretreatment of the vesicles with deprenyl, a specific monoamine oxidase type B inhibitor. The aldehydes formed in the course of enzymatic deamination of the substrates of type B, monoamine oxidases, are considered as possible participants in the regulation of Ca2+, Mg2+-dependent ATP-ase activity.

Adenosine Triphosphatases↗
PubMed1977

[Several kinetic features of membrane-dependent monoamine oxidase].

The v versus (S) plots for the initial rates of serotonin oxidation, catalyzed by monoamine oxidase in fragments of the rat liver or bovine brain mitochondrial membrane, had complicated non-hyperbolic shape, suggesting kinetic manifestation of cooperation in binding the substrate by the enzyme. A possibility of interactions of different monoamine oxidase types via the conformational alterations in the bio-membrane itself is considered.

Animals↗
PubMed1977

[Transformation of mitochondrial monoaminoxidases types A and B].

Chlorgyline, a selective monoamine oxidase (MAO) of the A type inhibitor, contrary to deprenil--MAO of the B type inhibitor, prevented the appearance in the rat liver mitochondrial membrane fragments incubated under aerobic conditions of qualitatively new properties to deaminate histamine or AMP. Apparently the MAO of A type but not of B type underwent a qualitative alteration (transformation) of catalytic properties under conditions favourable for partial oxidation of SH-groups.

Animals↗
PubMed1975

Stimulation of adenylate deaminase activity by serotonin.

After a single intraperitoneal injection of serotonin into rats adenylate deaminase activity in the mitochondrial fraction of the liver was stimulated. The conditions under which a twofold increase in the deamination of AMP occurred, after serotonin administration,were determined. Preliminary blocking of monamine oxidase activity did not prevent this effect of serotonin.

Adenosine Monophosphate↗
PubMed1975

Deamination of biogenic amines and other nitrogenous compounds in granulation tissue from experimental wounds.

In the granulation tissue of skin wounds an increase in the content of hydroxyproline was accompanied by changes in lipid peroxidation products. At the same time deamination of 5-hydroxytryptamine, tyramine or adenosine-5'-monophosphate decreased, but the ability to deaminate histamine, putrescine and lysine appeared. Pargyline prevented the appearance of these new deaminating properties. Adenosine-3'-monophosphate slowed down to the weight increase and lowered the content of hydroxyproline in the growing granulation tissue; it also changed the dynamics of deamination of tyramine or 5-hydroxytryptamine and significantly inhibited the deamination of histamine, lysine and adenosine-5'-monophosphate. The patterns of changes in deamination of nitrogenous compounds and the effects caused by pargyline and adenosine-3'-monophosphate suggest that qualitative alteration (transformation) in catalytic properties of monoamine oxidases may occur in the growing granulation tissue from wounds.

Adenosine Monophosphate↗
PubMed1975

[Specificity and mechanism of serotonin stimulation of adenylate deaminase activity].

Adenylate deaminating activity was stimulated in the liver mitochondria of rats in vivo not only by serotonin or synthetic indolylalkylamines, but also by phenyl- and imidazolalkyamines. Actinomycin D and cycloheximide protein biosynthesis inhibitors prevented stimulation of adenylate deaminating activity. Theophylline, phosphodiesterase inhibitor, produced a similar effect only when the extent of stimulation of adenylate deaminating activity was comparatively high.

AMP Deaminase↗
PubMedDate not supplied

The role of lipid peroxidation in the possible involvement of membrane-bound monoamine oxidases in gamma-aminobutyric acid and glucosamine deamination in rat brain. Focus on chemical pathogenesis of experimental audiogenic epilepsy.

Incubation of rat brain synaptosomes and mitochondria with LPO inducers (Fe2+ and ascorbate) was accompanied by a decrease of deamination of serotonin (substrate of MAO-A) in mitochondria, but not in synaptosomes, with simultaneous stimulation of GABA and GLCA deamination, apparently owing to modification of catalytic properties of brain membrane-bound MAO. Oxidation of PEA (substrate of MAO-B) was insignificantly altered in both fractions. Reactions of deamination of serotonin, GABA, and GLCA (but not PEA), were highly sensitive to a selective inhibitor of MAO-A pyrazidol (pyrlindole). Isoniazid and hydrazides of quinoline carbonic acids (inhibitors of both modified MAO and copper-containing amine oxidases) strongly inhibited deamination of GABA and GLCA. During epileptiformic seizures in rats, genetically selected for high incidence of audiogenic epilepsia, stimulation in brain synaptosomes and mitochondria of LPO was observed. This was accompanied by a marked decrease in serotonin and PEA deamination, with a simultaneous increase in GABA and GLCA deamination in both fractions. The data obtained suggest that appearance of GABA-deaminating activity owing to modification of catalytic properties of MAO, might be an essential pathogenetic component in the development of epileptic seizures.

Acoustic Stimulation↗