[Localization of tryptophan residues in Ca2+-ATPase from sarcoplasmic reticulum].

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.

[Effect of actoprotectors on Ca, Mg-dependent ATPase activity in the sarcoplasmatic reticulum of rabbit muscles].

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 effect of biologically active compounds on the enzymatic activity of sarcoplasmic reticulum (Ca2+,Mg2+)-dependent ATPase transformed by synthetic phospholipids].

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.

[Incorporation of synthetic phospholipids into the membranes of the sarcoplasmic reticulum from the rabbit muscle].

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.

[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].

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.

[Spectrofluorometric topography of the ATPase center of Ca2+-Mg2+-dependent ATPase of sarcoplasmic reticulum by means of platinum and palladium compounds].

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].

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.

[Mechanisms of the action of psychotropic preparations on transport ATPases].

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.

[Effect of platinum and palladium compounds on mitochondrial enzymatic systems].

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].

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.

[Induction of a menadione-dependent respiratory shunt by a platinum complex].

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.

[Spin-label progesterone binding to serum albumin].

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.

[Inhibition of membrane-bound adenosine triphosphatase by platinum and palladium salts].

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.

[Interaction of platinum and palladium complexes with thiol groups of Ca2+-dependent ATPase from sarcoplasmic reticulum].

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.

[Modeling non-enzymatic influence of membranes on the kinetics of chemical reactions].

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].

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.

[Effect of psychotropic and anticonvulsive preparations on transport ATPase in the renal tubules of the guinea pig].

The effect of 4 groups of medicamentous agents, viz. neoruleptics, tricyclic antidepressants, somnifacients and antiepileptics - on the activity of the transport ATPase and p-nitrophenylphosphatase from the renal tubules of the guinea pig was studied. Used in high concentrations neuroleptics suppress almost completely the activity of the enzyme, but in small doses influence but little that of the p-nitrophenylphosphatase.

[Effect of palladium and platinum salts on bacteriophage T4 and its isolated DNA].

The effect of palladium and platinum salts (K2PdCl4, K2PtCl4) on bacteriophage F4 and its isolated DNA in genetic transformation is investigated. Both compounds efficiently inactivated the phage and decreased the transforming activity of donor DNA. The palladium salt exhibited the higher activity.

[Interaction of pancreatic RNAase A with platinum ions].

Complex formation between RNAase and Pt(II) has been studied by gel filtration and conductometry, and spectrophotometry. Existence of three strong binding locations with the binding location of 2 times 10-4 M-1 has been stated. Effect of Pt(II) on hydrolase activity of RNAase Ahas been investigated.