[The lack of the effect of a strong constant magnetic field on isolated membrane preparations of Na,K-dependent ATPase]. / Ob otsutstvii vliianiia sil'nogo postoiannogo magnitnogo polia na izolirovannye membrannye preparaty Na,K-zavisimoi ATFazy.

Effect of constant magnetic field (CMF) with induction 10 T on membrane preparations of Na,K-dependent ATPase of bovine brain (lipoproteid vesicules with 300-500 A diameter) were studied. No CMF effect on the activity of Na,K-dependent ATPase was observed under different experimental conditions (three temperature points 15, 20 and 37 degrees C and great variation of Na+,K+ concentrations ratio). CMF also produced no effect on the preparations of Na,K-dependent ATPase immobilized by adsorption on millipore filters.

[Inhibition of respiration of mitochondria by o-phenanthroline in a constant magnetic field]. / Ingibirovanie dykhaniia mitokhondrii o-fenantrolinom v postoiannom magnitnom pole.

Preincubation of mitochondria treated with chelator of non-heme ferrum o-phenanthroline (0,067-0,267) for 20 min at 18 degrees C in the constant magnetic field of 330 mT brings about a decrease of the intensity of their uncoupled respiration with NAD-dependent substrates by 15-20% as compared to similar mitochondria preparations without the magnetic field effect. The latter is not realized during conjugated respiration with NAD-dependent substrates at uncoupled respiration with succinate, and in the absence of o-phenanthroline as well.

[Effect of digitonin on the activity of Na,K-ATPase from bovine brain]. / O vliianii digitonina na aktivnost' Na,K-ATPazy iz mozga byka.

The kinetic properties of intact and digitonin-treated Na,K-ATPase from bovine brain were studied. The temperature dependence curve for the rate of ATP hydrolysis under optimal conditions (upsilon 0) in the Arrhenius plots shows a break at 19-20 degrees. The temperature dependence curves for Km' and Km" have breaks at the same temperatures, while the Arrhenius plot for V is linear. The value of the Hill coefficient (nH) for ATP at 37 degrees is variable depending on ATP concentration, i. e. it is less than 1 at ATP concentrations below 50 mkM and is increased up to 3.2 at higher concentrations of the substrate. At high ATP concentrations the value of nH depends on temperature, falling down to 2.1 at 23 degrees and then down to 1 within the temperature range of 21-19 degrees. A further decrease in temperature does not significantly affect the nH value. Digitonin irreversibly inhibits Na, K-ATPase. ATP hydrolysis is more sensitive to the effect of the detergent than is nNPP hydrolysis, i. e. after complete inhibition of the ATPase about 40% of the phosphatase activity are retained. Treatment of Na,K-ATPase by digitonin results in elimination of the breaks in the Arrhenius plots for upsilon 0, Km' and Km", whereas the temperature dependence plot of V remains linear. Simultaneously digitonin eliminates the positive cooperativity of the enzyme for ATP. It is assumed that Na, K-ATPase from bovine brain is an oligomer of the (alpha beta) 4 type. Digitonin changes the type of interaction between the protomers within the oligomeric complex by changing the lipid environment of the enzyme or the type of protein -- lipid interactions.

[Mechanisms of the action of psychotropic preparations on transport ATPases]. / O nekotorykh mekhanizmakh deistviia psikhotropnykh preparatov na transportnye ATF-azy.

Psychotropic drugs, especially neuroleptics, reversibly and noncompetitively inhibit the activity of Na, K-ATPase of the brain and Ca, Mg-ATPase of the sarcoplasmatic reticulum. The inhibitory effect is more pronounced versus the sarcoplasmatic reticulum and less marked versus purified enzymatic preparations. It is not much dependable on variations in the protein concentration of enzymatic preparations and is not related to drug binding to sulfhydryl groups of an enzyme. The inhibitory action of the drugs declines or completely disappears after treating the membranous preparations with phospholipase A. That psychotropic drugs have a predominant effect on the lipid structure of the membrane was supported during examination of EPR spectra of lipid spin labels.

[Effect of platinum and palladium compounds on mitochondrial enzymatic systems]. / Vliianie soedinenii platiny i palladiia na fermentnye sistemy mitokhondrii.

Effect of platinum and palladium complexes on respiration and ATPase activity in bovine heart tissue as well as on respiration of submitochondrial particles was studied. The highest inhibitory activity was exhibited by the complexes of platinum and palladium with pi-ligands in internal coorhdinational sphere such as ethylene-C H4, norbornadiene-C7H8 and allyl-C3H5. The electron density at the central atom of the complex was not responsible for the inhibitory affect of platinum and palladium on mitochondria.

[Interaction of platinum and palladium 5-sulfo-8-mercaptoquinoline complexes with sarcoplasmic reticulum Ca2+-dependent ATPase]. / O mekhanizme vzaimodeistviia 5-sul'fo-8-merkaptokhinolinovykh kompleksov platiny i palladiia s Ca2+-zavisimoi ATPazoi sarkoplazmaticheskogo petikuluma.

5-Sulfo-8-mercaptoquinoline complexes of platinum and palladium (complexes I and II) effectively inhibit Ca2+-dependent ATPase from sarcoplasmic reticulum. However, in contrast to K2PtCl4, K2PdCl4 and other previously investigated platinum and palladium complexes, they do not interact with the thiol groups of the enzyme. The inhibiting effects of complexes I and II are reversible and competitive with respect to ATP. In aqueous solutions complexes I and II decrease the fluorescence of tryptophane with a simultaneous shift in fluorescence towards the long-wave region. The same effect is exerted by the complexes on the fluorescence of tryptophane residues in Ca2+-dependent ATPase preparations. An addition of tryptophane to the enzyme preparations preincubated with complexes I and II partly restores the enzyme activity. It is assumed that the inhibiting effect of complexes I and II is due to their non-covalent interactions with the trytophane residues vicinal to the ATPase center.

[Effect of beryllium salts on the activity of sarcoplasmic reticulum Ca2+,Mg2+-dependent ATP-ase]. / Vliianie solei berilliia na aktivnost' Ca2+,Mg2+-zavisimoi ATF-azy sarkoplazmaticheskogo retikuluma.

In the presence of Mg2+ and Ca2+ ions beryllium compounds inhibit the Ca2+, Mg2+-dependent ATPase activity and the transport of Ca2+ in the sarcoplasmatic reticulum vesicles. The inhibition is reversible and concurrent with respect to the Mg2+ ions. In the absence of the Mg2+ ions an addition of beryllium compounds stimulates the ATPase activity, the dependence of the degree of its stimulation on the beryllium compounds concentration is characterized by a curve with a maximum. On the membranous Ca2+, Mg2+-dependent ATPase preparations beryllium compounds produce a stronger inhibiting effect than in the case of the purified enzyme, which is, apparently, due to their ability to influence the membranous structure. The hydrophobic spin probe method shows that beryllium compounds reduce the microviscosity of the lipid sections of the membrane.

[Induction of a menadione-dependent respiratory shunt by a platinum complex]. / Induktsiia menadionsavisimogo dykhatel'nogo shunta kompleksom platiny.

Submitochondrial particles (SMP) from the bovine heart were treated with platinum complex--K [C2H4 PtCl3] (Zeize's salt); there occurred a menadion-dependent shunt, this being expressed in menadion stimulation of oxygen consumption under conditions of electron transport block with rotenon. This effect was observed only with the use in the capacity of a substrate of NAD.N2, but not of succinate. Menadion-dependent respiration induced with Zeize's salt was dicoumarol-sensitive, but was not inhibited by antimycin and cyanide, this differentiating it from menadionreductase shunt in the intact hepatic mitochondria.

[Interaction of platinum and palladium complexes with thiol groups of Ca2+-dependent ATPase from sarcoplasmic reticulum]. / Vzaimodeistvie kompleksov platiny i palladiia s tiolovymi gruppami Ca2+-zavisimoi ATF-azy sarkoplazmaticheskogo retikuluma.

In native preparations of sarcoplasmic reticulum 10-12 thiol groups (in g-eqv per 10(5) g of protein) were estimated by the Benesh method (titration with AgNO3) and 2 thiol groups--by Ellman (titration with dithionitrobenzoic acid). After denaturation of the sarcoplasmic reticulum preparations with 8 M urea 10-12 thiol groups were also determined by the Ellman method. When the preparations were treated with platinum tetrachloride or with palladium diaminodichloride, only 3 thiol groups were estimated by the Benesh and no one - by the Ellman method. Platinum and palladium complexes inhibited also the Ca2+-dependent activity blocking the transport of Ca2+ in sarcoplasmic reticulum. The inhibition was partially removed by glutathione.

[Inhibition of membrane-bound adenosine triphosphatase by platinum and palladium salts]. / Ingibirovanie membranosviazannoi adenozintrifosfatazy soliami platiny i palladiia.

Inhibition capacity of platinum and palladium complexes is studied on membrane-bound ADTP. The degree of inhibition of the enzyme activity is determined by the nature of the central atom and by the electron density on it, as well as by the ligand donor-acceptor capacity, by its mobility. The configuration of the complex and the charge of complex ion are of importance. The acidoligands studied according to their inhibition effect can be arranged in the following line: NO2, Cl, Br, SCN, I, which is true both for platinum and palladium compounds. For palladium complexes this line coincides with the location of ligands according to their ability to draw off the electron density from the central atom while in case of platinum complexes it has an opposite course of relationship for platinum and palladium complexes, points to a different mechanism of their interaction with the enzyme.

[Monoamine oxidase type B and the function of Ca2+, Mg2+-dependent adenosine triphosphatase of preparations of sarcoplasmic reticulum vesicles]. / Monoaminoksidaza tipa B i funktsii Ca2+, Mg2+-zavisimoi adenozintrifosfatazy preparatov vezikul sarkoplazmaticheskogo retikuluma

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.

[Inhibitory effect platinum and palladium complexes as indicator of conformational changes in sarcoplasmic reticulum membranes]. / Ingibiruiushchie effekty kompleksov platiny i palladiia kak indikator konformatsionnykh perekhodov v membranakh sarkoplazmaticheskogo retikuluma

Inhibition of Ca2+-dependent ATPase of sarcoplasmic reticulum membranes (SRM) by platinum and palladium complexes is considerable enhanced during the incubation of these compunds with SRM preparations in the presence of small (10(-5) M) concentrations of ATP or ADP. AMP and nucleotides with non-adenine bases do not have inhibitory effect. To increase the sensitivity of Ca2+-dependent ATPase to platinum and palladium complexes under the action of ATP (but not ADP), the presence of free Ca2+-ions in the medium is required. In the absence of ATP Ca2+-ions do not affect the inhibiting effect of the complexes. The increase in pH of the medium up to 8.5 and the increase of temperature up to 45degree C sharply decrease the ATP ability to enchance the sensitivity of Ca2+-dependent ATPase to platinum and palladium compunds. It is assumed that the ATP ability to enhance Ca2+-dependent ATPase inhibition by platinum and palladium complexes is due to ATP-dependent structural changes in SRM, which increase the availability of certain groups of the enzyme to those compounds.

[Effect of psychotropic preparations on the activity of Ca- and Mg-dependent ATPase of the sarcoplasmic reticulum]. / Vliianie psikhotropnykh preparatov na aktivnost' Ca, Mg-zavisimoi ATF-azy sarkoplazmaticheskogo retikuluma

In sarcoplasmic reticulum of rabbit skeletal muscles the activity of Ca2+, Mg2+- dependent ATPase was distinctly inhibited under effect of neuroleptic drugs - derivatives of phenothiazine and butyrophenone. The effect of tricyclic antidepressants was less pronounced. Tranquilizers (derivatives of 1,4-benzodiazepine) inhibited the enzyme, but trioxazin was only slightly active. High concentrations of lithium salts and of psychostimulants caffeine and corasole were found to stimulate the Ca2+, Mg2+-ATPase activity; low concentrations of the substances slightly inhibited the enzyme. The blocking effect of psychotropic drugs was more distinct, if the enzyme preparations were previously treated with ATP.

[Study of the interaction of human serum albumin with penicillins by means of spin labels]. / Issledovanie vazimodeistviia syvorotochnogo al'bumina cheloveka s penitsillinami metodom spinovykh metok

Interaction of 8 penicillin preparations with human serum albumin was studied with the spin-labels method and a probe. Correlation between the binding level of penicillins with human serum albumin and their effect on the spectrum of EPR of the spin-label attached to albumin was observed only with the use of a hydrophobic probe (radical III). The covalent attached marks and the hydrophobic probe may be used for rapid orienting estimation of pencillin interaction with albumin.

[Conformational transitions in Na, K-dependent ATPase]. / Konformatsionnye perekhody v Na, K-zavisimoi ATPaze

Conformational transitions in membrane preparations of Na, K-dependent ATPase were studied by means of mono-radical and bi-radical hydrophobic spine probes. A decrease in micro-viscosity of non-polar membrane regions in Na, K-ATPase preparation was observed under the formation of phosphorylated N, K-ATPase intermediate in the presence of ATP and Na+ ions. K+-catalysed dephosphorylation of the intermediate resulted in opposite changes. Bi-radical probes of a certain chemical structure turned to be the most sensitive indicators of conformational changes in membranes of Na, K-ATPase preparation. Na+-, K+- and ATP-induced conformational transitions are blocked with suabaine, a specific inhibitor of Na, K-ATPase, with Ca2+ oligomycin and p-chloromercuric benzoate (PCMB). K+-dependent transitions are more sensitive to oligomycin and PCMB as compared with those induced by ATP and Na+. Possible mechanisms of conformational transitions in Na, K-dependent ATPase are discussed.