[Blood cobalamins and xenobiotic-metabolizing enzymes in rat liver in adjuvant arthritis]. / Kobalaminy krovi i fermenty metabolizma ksenobiotikov v pecheni krys pri ad''iuvantnom artrite.

Changes in the total cobalamin content and spectrum of individual forms of these vitamins in blood cells and plasma as well as the activities of enzymatic systems of xenobiotic metabolism in liver microsomes of rats with experimental adjuvant arthritis (AA) have been studied. The total cobalamin content in the blood plasma of rats with AA was increased in comparison with intact animals; however, leucocytes from AA rats were deficient in methylcobalamin (MeCbl). A correlation was found between the ratios of individual cobalamin forms and their total content which was differently expressed in experimental and control animals. The development of AA was associated with marked inhibition of the cytochrome P-450-dependent monooxygenase system of the liver and glutathione transferase. The possibility of correction of these disturbances by MeCbl is discussed.

[The effect of ubiquinone-10 on the development of D-galactosamine-induced hepatitis in rats]. / Vliianie ubikhinona-10 na razvitie D-galaktozaminovogo gepatita u krys.

It has been shown that prophylactic administration of ubiquinone protects rats liver from the toxic damage by D-galactosamine both on ultrastructural and on cell levels. Ubiquinone administration prevents necrosis in hepatocytes and preserves their ability for compensatory reactions expressed in activation of protein-synthesis regulating structures in the cell. Ubiquinone decreases hyperfermentemia and hyperbilirubinemia as well as prevents the decrease in liver protein content caused by galactosamine. Ubiquinone exerts an antioxidant effect, blocking the induction of lipid peroxidation both in intact and hepatic rats.

[Supermolecular organization of aminotransferases and dehydrogenases of alpha-ketoacid from rat brain mitochondria]. / Hadmolekuliarnaia organizatsiia aminotransferaz i degidrogenaz alpha- ketokislot mitochondrii golovnogo mozga krys.

A fraction of coarse mitochondria from the rat brain was deposited after short-term effect of supersound to obtain "metabolones". Activity of dehydrogenases of alpha-ketoacids, succinate dehydrogenase, aspartate-, alanine- and GABA-alpha-ketoglutarate amino-transferases has been determined in the supernatant liquid and in "metabolones". It is shown that dehydrogenase activity is mainly (93-100%) localized in "metabolones", while the level of aminotransferase activity in the latter is lower (72-94%). Nonproportionally high activity of aminotransferases in the supernatant liquid is found to considerably suprpass a decrease in activity of these enzymes in "metabolones" against a background of extremely scanty losses of protein (within 5%) induced by the supersound effect. A hypothetic model of a "metabolone" containing the enzymes of the Krebbs cycle and GABA-shunt is suggested.

[Problems of biochemical organization]. / Problemy biokhimicheskoi organizatsii.

Biological organization has been defined as a unity of structure, function and regulation. Biological organization of hierarchical multilevel biological systems is represented by a hierarchy of functioning controllable structures. The hierarchy of levels of material organization predetermines the existence of a hierarchy of regulatory mechanisms. Biochemical organization involves the levels of material organization corresponding to biomacromolecules, supramolecular complexes and cellular organelles. The levels of biomacromolecules and supramolecular structures effectuating elementary functions and controlled by basic regulatory mechanisms occupy key positions in biological systems. These levels play the role of standard functional blocks; their combination leads to hierarchically higher structural levels (cell, tissue, organ, systems of organs, organism) performing more complex functions and controlled by hierarchically more important regulatory mechanisms. The peculiarities of regulation of biological systems that are due to the existence of a hierarchy of regulatory mechanisms are discussed.

[Principles of the organization and functioning of the metabolon microcompartment]. / Printsipy organizatsii i funktsionirovaniia mikrokompartmenta metabolona.

The approaches to the elucidation of principles of metabolon functioning and the applicability of concepts of "protein-machine" and "conjugated ionic hydrogen bond systems" are discussed. The term "metabolon" refers to a supramolecular complex of sequential metabolic enzymes and structural elements of the cell. It has been assumed that the metabolon microcompartment consists of separate units joined together by channels, in which the active and, possibly, allosteric sites of enzymes become approximated.

[Hypothetical structure of the glycolytic enzyme complex (glycolytic metabolon) formed on erythrocyte membranes]. / Gipoteticcheskaia struktura kompleksa fermentov glikoliza (glikoliticheskogo metabolona), formiruiushchegosia na membrane éritrotsitov.

A hypothetical structure of the glycolytic enzyme complex (glycolytic metabolon) adsorbed on the inner surface of the erythrocyte membrane has been proposed. Oligomers of integral membrane protein, band 3 protein (anion-transport system), are the anchor site for the complex. The complex is supposed to have a three-fold symmetry axis, perpendicular to the membrane plane, and contains a triple set of the glycolytic enzymes. The complex is in equilibrium with free enzymes; the equilibrium state depends on the physiological state of the erythrocyte.

[Supramolecular organization of enzymes of the tricarboxylic acid cycle]. / Nadmolekuliarnaia organizatsiia fermentov tsikla trikarbonovykh kislot.

In virtue of analysis of data on the interaction of tricarboxylic acid cycle enzymes with the mitochondrial inner membrane and data on the enzyme-enzyme interactions, the spatial structure for the tricarboxylic acid cycle enzyme complex (tricarboxylic acid cycle metabolon) is proposed. The alpha-ketoglutarate dehydrogenase complex, adsorbed on the mitochondrial inner membrane along one of its 3-fold symmetry axes, plays the key role in the formation of metabolon. Two association sites of the alpha-ketoglutarate dehydrogenase complex located on opposite sides of the complex participate in the interaction with the membrane. The tricarboxylic acid cycle enzyme complex contains one molecule of the alpha-ketoglutarate dehydrogenase complex and six molecules of each of the other enzymes of the tricarboxylic acid cycle, as well as aspartate aminotransferase and nucleosidediphosphate kinase. Succinate dehydrogenase, the integral protein of the mitochondrial inner membrane, is a component of the anchor site responsible for the assembly of metabolon on the membrane. The molecular mass of the complex (ignoring succinate dehydrogenase) is of 8.10(6) daltons. The metabolon symmetry corresponds to the D3 point symmetry group. It is supposed, that the tricarboxylic acid cycle enzyme complex interacts with other multienzyme complexes of the matrix and the electron transfer chain.