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Biomedical subjects

N V Kuleva

Publications and source records attributed to N V Kuleva.

16 recordsLinked to original sources
PubMed2006

[Dynamics of rat hepatocyte histone glycoxidation after general x-ray irradiation].

Dynamics of structural parameters of hepatocyte histone glucoxidative modification 3, 9 and 24 h after general X-ray irradiation of rats at dose 5 Gy was studied. Dynamics of these parameters (content of carbonyl groups, bityrosyl cross-linkings, pentosidines, advanced glycation end products) was compared with alterations in DNA structure (according to agarose gel electrophoresis) and lipid peroxidation extent (by malondialdehyde content). Oxidative stress induced by hepatocyte irradiation results in structural damage of DNA and histones accompanied by an increase of histone bityrosyl cross-linking and carbonyl content. The content of advanced glycation end products in histones corresponds to the extent to DNA damage and malondialdehyde content. The described postradiation modifications of histones may be important for regulation of chromatin function.

Animals↗
PubMed2000

[Nonenzymatic glycosylation of and oxidative damage to actin in vitro and in vivo].

A study was made the influence exerted by non-enzymatic glycosylation (glycation) and oxidative destruction on structural and functional parameters of actin (free NH2-groups, advanced glycation end product and bityrosine cross-linking content, DNase inhibition by G-actin and myosin Mg(2+)-ATPase activation by F-actin). The functional properties of actin were shown to change under high molecular weight product formation and oxidative destruction: the extent of DNAase I inhibition decreases (from 70 to 40%) and the extent of myosin Mg(2+)-ATPase decreases (by 40%). Carnosine prevents actin oligomer formation and oxidative destruction which favours preservation of the protein functional properties.

Actins↗
PubMed1997

Change in the functional properties of actin by its glycation in vitro.

The influence of glycation (non-enzymatic glycosylation) on structural and functional properties of actin of rabbit skeletal muscle and the effects of the natural anti-glycating dipeptide carnosine were studied. Glucose (0.5 M), fructose (0.5 M), and glyceraldehyde (0.05 M) were used as glycating agents. Marked changes in the structural and functional properties were observed in the presence of glyceraldehyde when high-molecular-weight components appear. This was followed by a decrease in the ability of actin to activate myosin ATPase, to polymerize, and to inhibit DNase I. In the presence of 0.05 M carnosine, the quantity of high-molecular-weight products decreased and myosin ATPase activation was retained. Since muscle tissue contains millimolar quantities of carnosine, glycation of actin associated with changes in its properties is evidently more likely to occur in non-muscle cells.

Animals↗
PubMed1991

Polarization microfluorimetry study of interaction between myosin head and F-actin in muscle fibers.

Changes in conformation of F-actin induced by the binding of myosin molecule subfragment 1 were studied in myosin-free single ghost muscle fibers with the method of polarization microfluorimetry. The modification of the structure of subfragment 1 by proteolytic digestion with one or two cuts in subfragment 1 or degradation of 50 kDa domain did not influence the character of changes in the conformation of F-actin. The use of preparations of subfragment 1 devoid of the 20 kDa domain or both cross-linked SH1 and SH2-groups changed the character of conformational rearrangements in F-actin. The present data show that a site of interaction with actin in the 20 kDa domain plays a key role in inducing the changes in actin conformation corresponding to a "strong" form of the binding. It is supposed that transmission of changes in the conformation of the myosin head to F-actin might be important for muscle contraction.

Actins↗
PubMed1988

[The effect of proteolysis of myosin heads on conformational changes induced by them in F-actin].

The effect of limited proteolysis of myosin subfragment I (S1) on conformational changes in F-actin during the formation of a rigor F-actin-S1 complex was studied, using polarized microfluorimetry. Upon the decoration of thin filaments made up of rhodaminyl-phalloin modified F-actin with subfragment I, the anisotropy of fluorescence increased. Limited proteolysis of S1 at the junctions of 27 kD-70 kD and 27 kD-50 kD-20 kD fragments as well as the destruction of the 50 kD fragment by methanol had no effect on the nature of these changes. It was assumed that during the formation of the actomyosin complex the conformational changes in F-actin were induced by the 20 kD fragment. The 27 kD and 50 kD fragments seemed to exert a weak influence on action conformation within the complex.

Actins↗
PubMed1986

[Nerve cell myosin].

Explore the source record for details and available documents.

Adenosine Triphosphatases↗
PubMed1983

[Study of dynein ATPase by oxygen isotope exchange H2(18)O in equilibrium with [16O]-Pi].

The oxygen isotope exchange reactions catalyzed by sea urchin Strongylocentrotus intermedius spermatozoa dynein I were studied with a view of comparing molecular mechanisms of ATP hydrolysis by dynein and myosin ATPases. It was demonstrated that the isotope exchange takes place during ATP hydrolysis and during enzyme incubation with ADP and Pi and is absent when the enzyme is incubated with Pi. It was assumed that the molecular mechanisms of ATP hydrolysis by dynein I and myosin are identical.

Adenosine Triphosphatases↗
PubMed1982

A study of the 18O-exchange reactions catalyzed by cardiac myosin and its subfragment 1.

Isotope-exchange reactions (H2(18)O in equilibrium with KH2PO4) during ATP hydrolysis catalyzed by myosin and its subfragment 1 from rabbit, dog, and human cardiac muscle were studied. All preparations of myosin and subfragment 1 in the presence of Mg2+ catalyzed two types of 18O-exchange reactions similar to those of skeletal muscle: intermediate and direct 18O exchange. The dependences of both reactions on divalent metals and nucleotides were studied. Data on 18O exchange of subfragment 1 from rabbit, dog, and human cardiac muscle were obtained for the first time. They indicate the similarity of molecular mechanisms of ATP energy use in cardiac and skeletal muscle contraction.

Actomyosin↗
PubMed1977

18O-exchange catalyzed by myosin, heavy meromyosin, heavy meromyosin subfragment 1 and their complexes with actin.

Myosin, HMM and HMM S1 catalyze 18O-exchange between P1 and H218O of the medium at an intermediate stage of ATP hydrolysis ("intermediate 18O-exchange") in the presence of Mg2+. Natural complexes of actomyosin and acto-HMM S1 do not catalyze intermediate 18O-exchange but facilitate "direct" or "medium" 18O-exchange (KH2P18O4 in equilibrium H2O) even without ATP. Reconstituted complexes of actomyosin, acto-HMM, acto-HMM S1, PABC-HMM S1, congo-myosin and TNP-myosin do not catalyze direct 18O-exchange in the presence of Mg2+ and absence of ATP. From the data obtained a hypothetical sequence of phosphorylation and 18O-exchange reactions in myofibril action has been suggested.

Actins↗
PubMed1977

[Oxygen isotope exchange reactions in synaptosomal plasmatic membrane system].

Mg2+-Dependent, Ca2+-activated adenosine triphosphatase (E. C. 3.6.1.4) of synaptosomal plasmatic membrane from cow brain catalyses isotopic exchange of oxygen atoms: KH2P18O 4 in equilibrium H2O, the degree of exchange depending on Ca2+ concentration. The 18O-exchange catalysis suggests that the enzyme under consideration acts as a transport ATPase.

Adenosine Triphosphatases↗
PubMed1977

[18 O-exchange reactions catalyzed by myosin of calf intestine smooth muscle].

18O-exchange reactions of smooth muscle myosin of calf intestine were studied. Smooth muscle myosin, similar to skeletal myosin, catalyses two types of 18O-exchange reactions--intermediate and direct. Only quantitative differences of the exchange intensity are observed. 18O-exchange dependence on bivalent cation and nucleotide nature is found. The comparison of 18O-exchange characteristics for myosins of smooth and skeletal muscles confirms the hypothesis on the similarity of molecular mechanisms of ATP hydrolysis by myosin from different muscle types.

Adenosine Triphosphate↗
PubMedDate not supplied

[18O-exchange reactions in skeletal, cardiac and smooth muscle myosin].

18O-exchange reactions of skeletal, cardiac and smooth muscle myosin were studied. All investigated preparations of myosin catalyse two types of 18O-exchange--intermediate and direct exchanges in the presence of Mg2+. The dependence of 18O-exchange extent on divalent cations have appeared to be similar for different muscle types. This supports the hypothesis of similarity of ATP hydrolysis molecular mechanisms by myosin of different origin.

Animals↗