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G V Lebedeva

Publications and source records attributed to G V Lebedeva.

16 recordsLinked to original sources
PubMed2004

Kinetic model of imidazologlycerol-phosphate synthetase from Escherichia coli.

Based on the available experimental data, we developed a kinetic model of the catalytic cycle of imidazologlycerol-phosphate synthetase from Escherichia coli accounting for the synthetase and glutaminase activities of the enzyme. The rate equations describing synthetase and glutaminase activities of imidazologlycerol-phosphate synthetase were derived from this catalytic cycle. Using the literature data, we evaluated all kinetic parameters of the rate equations characterizing individually synthetase and glutaminase activities as well as the contribution of each activity depending on concentration of the substrates, products, and effectors. As shown, in the presence of 5 -phosphoribosylformimino-5-aminoimidazolo-4-carboxamideribonucleotide (ProFAR) and imidazologlycerol phosphate (IGP) glutaminase activity dominates over synthetase activity at sufficiently low concentrations of 5 -phosphoribulosylformimino-5-aminoimidazolo-4-carboxamideribonucleotide (PRFAR). Increased PRFAR concentrations resulted in decreased contribution of glutaminase activity and, consequently, increased the contribution of synthetase activity in the enzyme functioning.

Aminohydrolases↗
PubMed1992

[The intracellular pH of the peripheral blood lymphocytes in cattle during the development of leukemia].

The intracellular pH distribution of peripheral cattle lymphocytes has been studied in normal state and at six stages of the development of bovine leukosis by the dye microfluorimetry of single cells. It has been shown that the increase of mean intracellular pH value occurs as well some distribution parameters, such as pH range and asymmetry change during the disease process. Probable reasons responsible for the observed modification of the distribution pattern are discussed.

Animals↗
PubMedDate not supplied

[Regulation levels of photosynthesis processes].

The basic mechanisms of kinetic regulation of photosynthetic processes are considered, which provide a strict light regulation of electron transfer in photosynthetic reaction centers and a more flexible regulation at the level of interaction of photosystems, transmembrane ion fluxes and coupling with dark reactions of the Calvin cycle. A generalized model was developed, which integrates the modern knowledge about photosynthetic processes of higher plants. The general principles of multilevel regulation in photosynthetic systems are discussed.

Electron Transport↗
PubMedDate not supplied

[Kinetic model of primary processes of photosynthesis in chloroplasts. Fast phase of chlorophyll fluorescence induction under light of various intensity].

A kinetic model was developed, which describing the system of generation and consumption of the transmembrane electrochemical proton potential delta mu H+ in primary photosynthetic processes. The model describes the catalytic cycles of photosystems I and II and the cytochrome b/f complex, as well as the ATP synthesis and passive leakage of H+, K+ [symbol: see text] Cl- ions through the thylakoid membrane. The dependence of the electron transfer rates on the value of transmembrane electric potential was taken into account. The model was applied to describe the experimental data on the registration of the fast phase of fluorescence induction. The model gives a realistic description of the fast phase of induction curves at different light intensities (from high to low).

Adenosine Triphosphate↗
PubMedDate not supplied

[A kinetic model of the cytochrome bf complex. Evaluation of kinetic parameters].

A kinetic model of the cytochrome bf complex was developed on the assumption that the Q-cycle operates. The bf complex was considered as a membrane enzyme catalyzing the electron transfer from plastoquinol to plastocyanine, which is coupled with proton translocation from the chloroplast stroma to the thylakoid lumen. The dependence of the electron transfer rates on the value of the transmembrane electric potential was taken into account. The model was applied to describe the experimental data on the flash-induced turnover of cytochromes b, plastocyanine, and the kinetics of proton deposition in the thylakoid lumen. The estimation of model parameters was performed.

Cytochrome b6f Complex↗
PubMedDate not supplied

[A system of diagnostic tests, the providing of medical equipment and the level of automation in ambulatory care clinics].

Some problems of establishing the complex of diagnostic investigations based on the use of medical instrumentation in outpatient clinics with 50 000 and more population being served are discussed. The methodology to evaluate informative signs according to every diagnostic examination is presented. Computational relationships for quantitative evaluation of informative signs are given as well as an algorithm of generalized examination results reporting.

Ambulatory Care Facilities↗
PubMedDate not supplied

[Oscillations of intracellular pH values and the character of its distribution in immunocompetent cell populations].

Experimental measurements of intracellular pH kinetics detect intracellular pH (pHin) rhythms with a period about an hour and an amplitude comparable with the standard deviation of pHin in cell population. It was shown that pHin oscillations were probably to affect the experimental pH-distribution pattern. The pH-distribution of the population at normal physiological state is usually close to the normal pattern. The time-course of the pHin value for the cell population was shown to have a pattern of a kind of beatings to get the normal pH-distribution. Distributions of several "beating"--functions were used to approximate an experimental pH-distribution of immunocompetent cell population.

B-Lymphocytes↗