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Biomedical subjects

R I Gvozdev

Publications and source records attributed to R I Gvozdev.

28 records · Page 2Linked to original sources
PubMedDate not supplied

[Estimation of the distance between the iron-sulfur cluster of Fe-protein and the nearest iron-sulfur cluster of Mo-Fe-protein of nitrogenase on the basis of the inductive-resonance theory of energy transfer].

The distance between fluorescein mercuric acetate (FMA), attached to the HS-group of Fe- and Mo-Fe-protein, and the nearest iron-sulphur cluster (ISC) was determined. For Fe-protein the distance was 18--20 A and for Mo-Fe-protein 12--14 A. The distance between Fe-protein FMA and the nearest Mo-protein ISC determined by complementation of the labelled Fe-protein and native Mo-Fe-protein was 14--16 A. The distance between MO-OFe-protein ISC and complement Fe-protein ISC was 18--20 A. A te-protein ISC permitted to suppose that the electron was transfered from Fe-protein ISC to Mo-Fe-protein ISC by the contact of the ISC or with the help of ATP molecule.

Binding Sites↗
PubMedDate not supplied

[Method for assaying methane monooxygenase activity by measuring methane uptake in the reaction vessel].

The reaction vessel has been designed to measure methane monooxygenase activity. An elastic membrane has been built into one of the walls of the vessel to take liquid samples, avoiding formation of the gaseous phase in the reaction volume. The methane content in the samples is measured in a gas-liquid chromatograph with a flame ionization detector in two ways: 1. by direct measurement of methane in the liquid sample, and 2. by measurement of methane in the gaseous phase after methane diffusion from the liquid sample into the gaseous space of another vessel. The method is simple, sensitive (with a lower limit of 0.1 nMole CH4), and well reproducible. This method permits measurement of the oxidation kinetics of methane and other gaseous hydrocarbons both by intact cells and cell-free preparations of methane oxidizing bacteria.

Chromatography, Gas↗
PubMedDate not supplied

[Study of the amino acid residue topography of the adenosine triphosphatase center of (Ca--Mg)-dependent sarcoplasmic reticulum adenosine triphosphatase by kinetic and spectral methods].

The topography of HS- and NH2-groups and tryptophane residues in ATPase centre of (Ca--Mg)-ATPase on sarcoplasmic reticulum (SR) was investigated by kinetics, electron spectroscopy and spectrofluorimetry method. Both o-phthalaldehyde interacting with lysine or arginine residue or with end amino acid and fluorescein dimercuric acetate interaction with cysteine residue of HS-groups make (Ca--Mg)-ATPase both in SR and the pure enzyme completely inactive at molar ratio enzyme: inhibitor equal to 1 : 1. A 500 molar ATP surplus reduces drastically the enzyme inactivation rate by both inhibitors. The data supplied by the spectrofluorimetry and the induction-resonance theory were used to calculate the distances between nearest tryptophane residues and chromophore (o-FTC) generated by o-phthalaldehyde interaction with NH2-group the protein amino acid residue (17 A) and o-FTC and fluorescein dimercuric acetate (19 A) attached to enzyme HS-group. Because o-FTC is inside the protein pocket it is not accessible to J- ions up to 2.5 M KJ. However some tryptophane resudies and fluorescein dimercuric acetate attached to HS-group are near to the macromolecule surface. Lysine (or arginine residues) or end amino acid NH2-group and cysteine residues HS-group, and some tryptophane residues are at ATPase centre of (Ca--Mg)-ATPase from sarcoplasmic reticulum. Possible topography of the centre is discussed.

Amino Acids↗