[Influence of mediator diffusion on trigger mode of a synapse].

The model of postsynaptic membrane activation, is proposed in the paper. This model takes into account inhomogeneity of mediator's space distribution in the region of the synaptic cleft as well as nonlinear nature of interaction between the mediator and receptors on the postsynaptic membrane. Based on equations of this model stationary solutions are calculated for mediator distribution in the synaptic cleft and the number of activated receptors. Kinetics of reactions for activation and deactivation of receptors is analyzed within the concept of a trigger mode of the synapse. It is shown that activation-deactivation processes and redistribution of the mediator in the cleft can be interpreted as successive transitions between two stationary states of the system. Time of transitions between these states is found and its dependence on system parameters (in particular on the width of the synaptic cleft) is analyzed.

Excimer laser pumped by an intense, high-energy heavy-ion beam.

High-energy heavy ions are an ideal tool to generate homogeneously excited, extended volumes of nonthermal plasmas. Here, the high-energy loss (dE/dx) and absolute power deposition of heavy ions interacting with matter has been used to pump an ultraviolet laser. A pulsed 70 MeV/u 238U beam with up to 2.5 x 10(9) particles in approximately 100 ns beam bunches was stopped in a 1.2 m long laser cell filled with a 1.6 bar Ar-Kr-F2 mixture (typically 50%:49.9%:0.1%). Laser effect on the 248 nm KrF* excimer transition is clearly demonstrated.

Proposal for the study of thermophysical properties of high-energy-density matter using current and future heavy-ion accelerator facilities at GSI Darmstadt.

The subject of high-energy-density (HED) states in matter is of considerable importance to numerous branches of basic as well as applied physics. Intense heavy-ion beams are an excellent tool to create large samples of HED matter in the laboratory with fairly uniform physical conditions. Gesellschaft für Schwerionenforschung, Darmstadt, is a unique worldwide laboratory that has a heavy-ion synchrotron, SIS18, that delivers intense beams of energetic heavy ions. Construction of a much more powerful synchrotron, SIS100, at the future international facility for antiprotons and ion research (FAIR) at Darmstadt will lead to an increase in beam intensity by 3 orders of magnitude compared to what is currently available. The purpose of this Letter is to investigate with the help of two-dimensional numerical simulations, the potential of the FAIR to carry out research in the field of HED states in matter.

[Precipitation of cytochromes c with complex cadmium iodide]. / Osazhdenie tsitokhromov c kompleksnym iodidom kadmiia.

Using cytochrome c from horse heart and the yeast candida valida as examples, it was shown that a complex anion, cadmium tetraiodide (CdI42-), precipitated proteins from aqueous solutions at the reagent concentrations below 50 mM. The composition and pH value of the solution, as well as the starting protein concentration, considerably influenced the precipitation. The results suggest that this reagent acts on the protein by a mechanism similar to the salting-out process. The ability to act at small concentrations is the advantage of CdI42- over conventional agents.

[Plasma-desorption mass spectrometry of natural compounds. 1. Basic properties of the method and its use for analyzing proteins and peptides]. / Plazmenno-desorbtsionnaia mass-spektrometriia prirodnykh soedinenii prirodnykh soedinenii. 1. Osnovnye svoistva metoda i ego primenenie dlia analiza belkov i peptidov.

Applications of plasma desorption mass spectrometry (PD MS) to the analysis of natural substances are reviewed with the special emphasis on its use in peptide and protein chemistry (Part I). PD MS of nucleotides, carbohydrates, lipids, and pigments will be reviewed in Part II (see the following issue of this journal). The review covers the literature from 1982 to 1994.

[A tryptic heme peptide of cytochrome c from Candida valida]. / Tripticheskii gempeptid tsitokhroma c Candida valida.

Method for direct isolation of heme peptide from enriched yeast biomass have been developed. This method makes it possible to eliminate the process of cytochrome c purification. Amino acid sequence for the Candida valida heme peptide is proposed. Exact molecular masses for both cytochrome c and its heme peptide are determined by mass-spectrometry.

[Spatial organization of cytochrome oxidase subunit II]. / Prostranstvennaia organizatsiia sub''edinitsy II tsitokhromoksidazy.

We have studied the tryptic digestion and cyanogen bromide cleavage of the tritium-labelled subunit II from bovine cytochrome oxidase. Basing on the radioactivity distribution in the peptides obtained we suggest a model for the spatial structure of the title subunit.

[Isolation of the tritium labeled subunit II of cytochrome oxidase]. / Vydelenie mechennoi tritiem sub'edinitsy II tsitokhromoksidazy.

Radioactively labelled subunit II of cytochrome oxidase is isolated after irradiation of molecular crystals of the enzyme with thermally activated tritium.

[Structure and properties of cytochrome oxidase]. / Stroenie i svoistva tsitokhromoksidazy.

Recent data on the isolation and purification methods of cytochrome oxidase and its subunits are reviewed. Data are discussed on the enzyme's arrangement in the membrane, on the subunit composition and topology, localization of prosthetic groups, interaction of cytochrome oxidase with cytochrome c.

[Study of the interaction between cytochrome c and cytochrome oxidase by tritium planigraphy]. / Issledovanie vzaimodeistviia tsitokhroma c s tsitokhromoksidazoi metodom tritievoi planigrafii.

Treatment of molecular crystals of the bovine cytochrome oxidase and the cytochrome oxidase-cytochrome c complex with thermally activated tritium leads to highly labelled cytochrome oxidase preparations. HPLC separation of its subunits and measurements of radioactivity of each polypeptide allow to determine the shielding of cytochrome oxidase surface sites by cytochrome c in the complex.

[Protective effect of alpha-tocopherol on the Ca2+-transport system of the sarcoplasmic reticulum membranes in hypercholesterolemia]. / Zashchitnoe vliianie al'fa-tokoferola na Ca2+-transportiruiushchuiu sistemu membran sarkoplazmaticheskogo retikuluma pri giperkholesterinemii.

The effect of antioxidant--alpha-tocopherol--on Ca2+-transporting system in sarcoplasmic reticulum (SR) of the rabbit skeletal muscles was studied in hypercholesterolemia (HC). alpha-tocopherol administration to animals with HC produced a break on the curve of temperature dependence of Ca-ATPase activity at about 20 degrees C, that disappeared in HC, increased the rate of "rapid" SH-group binding by thiol reagents, and normalized the level of unsaturated fatty acids in SR membranes without altering phospholipid content. It is suggested that the damage of Ca-ATPase in HC is mainly due to activation of lipid peroxidation.

[Highly effective liquid chromatography of cytochrome oxidase polypeptides]. / Vysokoéffektivnaia zhidkostnaia khromatografiia polipeptidov tsitokhromoksidazy.

HPLC of the beef heart cytochrome oxidase subunits on TSKgel-column has been studied. It was found that the resolution of the subunits depends on the sodium dodecyl sulphate and buffer concentration. Strong interaction of subunits Va, VIc and VIIb with hydrophobic polypeptide chains was observed.

[The polypeptide composition of cytochrome oxidase from the bovine heart muscle]. / Izuchenie polipeptidnogo sostava tsitokhromoksidazy iz serdechnoi myshtsy byka.

The beef heart cytochrome oxidase (EC 1.9.3.1) has been purified by hydrophobic chromatography. The enzyme has been resolved into 11 different polypeptides by SDS/urea gel-electrophoresis.