[Localization of tryptophan residues in Ca2+-ATPase from sarcoplasmic reticulum]. / Lokalizatsiia triptofanovykh ostatkov v Ca2+-ATFaze sarkoplazmaticheskogo retikuluma.

By the methods of spectroscopy, fluorimetry and chemical modification of tryptophane residues with N-bromsuccinimide, the sarcoplasmic reticulum of rabbit sceletal muscle was shown to contain 18 +/- 1 tryptophane residues per Ca2+-ATPase molecule, 6 of which were, probably, inside the protein globule, in its hydrophobic region, and thus unavailable for modifier, while the rest 12 +/- 1 were easily transformed to the 6-oxyindole chromophore being the main source of the intrinsic fluorescence of the enzyme. The quantum yield for the rest four residues was equal to 0.015. Four tryptophane residues are located at the distance of less than 14 A from the ATP-binding site of the enzyme. The quantum yields of fluorescence for 8 of the tryptophane residues of Ca2+-ATPase were similar and equal to 0.03.

[Effect of actoprotectors on Ca, Mg-dependent ATPase activity in the sarcoplasmatic reticulum of rabbit muscles]. / Vliianie aktoprotektorov na aktivnost' Ca, Mg-zavisimoi ATFazy sarkoplazmaticheskogo retikuluma iz myshts krolika.

The effect of different chemical compounds on Ca, Mg-dependent ATPase (Ca-ATPase) sarcoplasmic reticulum (SR) hydrolytic activity as well as their actoprotecting (AP) activity, the ability to increase organism's resistance under muscle stress and antihypoxanthic (AH) activity to increase the organism's survival under conditions of low pressure has been studied. The compounds with AP-activity have been shown to be strong inhibitors of Ca-ATPase SR hydrolytic activity. No correlation between AP-activity of the compounds and their effect on Ca-ATPase SR has been found. The membranotropic activity of actoprotectors has been shown by electronic paramagnetic resonance method. A suggestion has been made to use Ca-ATPase SR as a tested object during the forecasting actoprotecting activity of new chemical compounds.

[The effect of biologically active compounds on the enzymatic activity of sarcoplasmic reticulum (Ca2+,Mg2+)-dependent ATPase transformed by synthetic phospholipids]. / Vliianie biologicheski aktivnykh soedinenii na fermentativnuiu aktivnost' rekonstruirovannoi sinteticheskimi fosfolipidami (Ca2+,Mg2+)-zavisomoi ATP-azy sarkoplazmaticheskogo retikuluma.

Aminasine, BeSO4 and Pt-5-sulfomercaptoquinolinate action on Ca-ATPase of SR showed a considerably less inhibiting effect as compared with that produced on the native membranes. The inhibiting action of the chemical compounds on those of native SR membranes is followed by the increase of mobility of hydrophobic segments of the membrane. The kinetic study of ATPase reaction at various temperatures showed on low-temperature transformation after the action by chemical compounds. Both structural transformations retain in the modified SR membrane independent of the chemical treatment. The activation energies considerably differ from those of native an modified membranes without chemical treatment (particularly in the region of 10-20 degrees). The data obtained allow to suggest that the inhibiting action of chemical compounds is followed by the changes in microviscosity (in the region of protein-lipid interaction of SR membrane, in particular), which by conformation transformations affect the configuration of the enzyme active center, alternating its geometry and catalytic activity.

[Incorporation of synthetic phospholipids into the membranes of the sarcoplasmic reticulum from the rabbit muscle]. / Vstraivanie sinteticheskikh fosfolipidov v membrany sarkoplazmaticheskogo retikuluma iz myshts krolika.

The hydrophobic spin label used in ESR showed that the iminoxyl radical rotation in the native membrane of sarcoplasmatic reticulum (SR) occurred much faster than in the membranes, modified by a synthetic lipid. Such effect was observed throughout the whole temperature range (7-40 degrees). Experimental technique for the modification of the SR membrane and the lipid by ultrasonic treatment has been developed. Synthetic lipids without ultrasonic treatment did not inhibit the activity of Ca2+-ATPase. The change in both the enzyme activity and its ability to transport the Ca2+ ions through the membrane vesicules was observed after the phospholipids incorporation into the SR membrane. The investigation of the temperature dependence (in Arrhenius coordinates) of native and modified by lecithin Ca2+-ATPase after ultrasonic treatment and also of a "pure enzyme" showed the presence of two sharp breaks at 20 degrees and 40-42 degrees. It was shown tha the break of an Arrhenius anamorphosis was caused by a lipid environment of ATPase, "melting" of a phospholipid bilayer. The break at 20-22 degrees was observed in all cases and even after the incorporation of all the lipids into the SR membrane. This phenomenon can be explained by the distortion of the protein-lipid interaction, affecting the conformation mobility of protein and the geometry of its catalytically active center.

[Comparative study of the mechanism of action of biologically active substances on the membrane-bound mitochondrial monoamine oxidase and Ca2+, Mg2+-dependent ATPase of the sarcoplasmic reticulum]. / Sravnitel'noe issledovanie mekhanizma deistviia biologicheski aktivnykh soedinenii na membranosviazannuiu mitokhondrial'nuiu monoaminoksidazu i Ca2+, Mg2+-zavisimuiu ATF-azu sarkoplazmaticheskogo retikuluma.

Mechanism of interaction between biologically active substances and membranes as well as and membrane-bound enzymes of two types: mitochondrial monoamine oxidase (MAO) from rat liver tissue and Ca2+, Mg+2-dependent ATPase from sarcoplasmic reticulum (SR) were studied. All the substances studied inhibited most distinctly the SR ATPase as compared with mitochondrial MAO. EPR technique enabled to detect that BeSO4, aminazine, Pt- and Pd-5-sulpho-8-mercaptoquinolinate affected the membranes of both types decreasing the microviscosity in its hydrophobic part. K2PtCl4 and K2PdCl4 altered the conformation of membrane proteins. All the substances studied were bound by the same amino acid residues of proteins and affected similarly the structure lability of these membranes. As distinct from MAO, interaction of the substances with active sites of ATPase was responsible for pronounced differences in the inhibitory effect of the same substances on various membrane enzymes. Transformation of MAO, accompanied by a decrease in viscosity of hydrophobic part of mitochondrial membrane, contributed to appearance of new enzymatic properties, which appear to occur due to alteration in the protein conformation and to redistribution of the enzyme reactive sites situated relatively close to the membrane surface.

[Spectrofluorometric topography of the ATPase center of Ca2+-Mg2+-dependent ATPase of sarcoplasmic reticulum by means of platinum and palladium compounds]. / Spektrofluorimetricheskoe issledovanie topografii ATP-aznogo tsentra Ca2+-Mg2+-zavisimoi ATP-azy sarkoplazmaticheskogo retikuluma s pomoshch'iu soedinenii platiny i palladiia.

The fluorescence of tryptophan residues in Ca2+--Mg2+-ATPase was studied in the presence of K2PtCl4, K2PdCl4 and 5-sulpho-8-mercaptochinolinate platinum and palladium. It has been shown that both first two compounds quenched the fluorescence dye to bonding with SH-groups in ATPase active centre, but the last two compounds influence the fluorescence by bonding with tryptophan residues. The distance between the SH-groups and tryptophan in the active centre was determined by Foerster--Galanin equation and was equal to 14 +/- 3 A.

[Ion transport through thick liquid membranes by fatty acids]. / Perenos ionov zhirnymi kislotami cherez tolstye zhidkie membrany.

Ion transfer through bulk liquid membrane induced by free fatty acids has been studied. Dependence of the rate of ion transfer upon pH change, salt concentrations, concentration and length of fatty acids and the type of cation has been obtained. These effects have been found both in H+ concentration gradient and cations of monovalent metals. It was shown that magnesium chloride inhibited the ion transfer. The scheme of stimulation with fatty acids of H+ electroneutral exchange for the cations of alkali metals has been proposed. It is supposed that the mode of action of fatty acids is more similar to nigericin than to the uncouplers of oxidative phosphorylation.

[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.

[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.

[Spin-label progesterone binding to serum albumin]. / Issledovanie sviazyvanie spin-mechenogo progesterona s syvorotochnym al'buminom.

The binding of spin label progesterone to bovine serum albumin was studied by the spin-probe technique. The binding capacity of protein was established. It was shown that protein formed a rigid complex with steroid, the correlation time of this complex being 50 ns. In the complex the radical part of the steroidal molecule has a hydrophobic environment.

[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.

[Modeling non-enzymatic influence of membranes on the kinetics of chemical reactions]. / Modelirovanie nefermentnogo vliianiia membran na kinetiku khimicheskikh reaktsii

The reduction of nitroxide radicals by rho-phenylene diamine was studied in H2O, various organic solvents in liposome suspensions and oleic acid emulsion. Some new parameters, particularly the presence of acids, appeared to effect the rate of the process. The results obtained are consistent with the hypothesis that the electron transport in coupled membranes leads to the production of undissociated acids thus supplying protons for the ATP synthesis.

[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.