PubMed Health⌕ Search

Biomedical subjects

V I Shvets

Publications and source records attributed to V I Shvets.

At least 55 records · Page 3Linked to original sources
PubMed1992

Use of biospecific interactions of collagen, fibronectin and their fragments in affinity chromatography.

Various aspects of the application of fibronectin-collagen biospecific interactions in affinity chromatography are described. A new biospecific method for one-stage isolation of collagen peptides containing fibronectin-binding sites is proposed. The alpha 1 CB7-peptide of type-I collagen cyanogen bromide cleavage was isolated by means of affinity chromatography on adsorbents containing an immobilized gelatin-binding domain (45,000 relative molecular mass) of fibronectin. The method gives highly purified preparations of alpha 1 CB7-peptide. This peptide, as well as some other collagen molecular fragments (alpha-chains, beta-components, alpha 1 CB8-peptide), were immobilized on Sepharose, and the properties of such affinity adsorbents obtained were studied. Adsorbents with immobilized alpha-chains and alpha 1 CB7-peptide had a fibronectin-binding capacity 1.5-2.0 times higher than commercial gelatin-Sepharose. Large-scale production of highly purified fibronectin from human plasma, using affinity chromatography on immobilized individual alpha-chains of collagen, was developed.

Binding Sites↗
PubMed1991

Proteolytic fragment of protein kinase C (kinase M) phosphorylates in vitro phosphatidylinositol-4-phosphate.

Limited tryptic proteolysis of homogeneous protein kinase C induces the formation of a catalytically active fragment of 50 kDa (kinase M) which, unlike native PK C acquires the ability to phosphorylate PIP. Both ATP and GTP were found to be capable of serving as phosphate donors in this process. Incubation of purified kinase M with a preparation of rat brain membrane fraction enhanced the level of phosphorylation of PIP in the presence and in the absence of exogenous PIP. A scheme of the interrelationship of phosphoinositide metabolism and the proteolytic processing of protein kinase C is proposed.

Adenosine Triphosphate↗
PubMed1991

Preparative isolation of polyphosphoinositides and other anionic phospholipids from natural sources using chromatography on adsorbents containing primary amino groups.

A new method for the preparative isolation of anionic phospholipids with the use of chromatography on adsorbents containing primary amino groups has been developed. The method combines elements of bioaffinity and ion-exchange chromatography. Synthesis of adsorbents based on Spheron and silica supports with immobilized neomycin, L-lysine, or aminoalkyl groups was carried out. Optimal conditions for the separation of phospholipid mixtures on aminosorbents were determined. Separation of rat brain bis- and trisphosphoinositides and preparative isolation of bovine heart cardiolipin and baker's yeast phosphatidylinositol are described. The chromatographic behavior of anionic phospholipids on three types of adsorbent was studied. The contribution of biospecific interactions to the adsorption of polyphosphoinositides on aminosorbents is noted.

Adsorption↗
PubMed1991

Acyclic analogs of dideoxydidehydronucleosides.

A new type of acyclic nucleoside analogs is proposed, containing C5 hydroxyalkyl fragments, where the distance between 5'-hydroxyl group and the heterocyclic moiety corresponds to that in dideoxydidehydronucleosides (as confirmed by computer modelling). Condensation between 5-0-acetyl-1-bromo-2-pentene and persilylated heterocyclic bases (pyrimidines and guanine) or adenine sodium salt gives rise to the acyclic nucleosides (5a-d, 6a-d) with the yields ranging from 40% up to 85%. Deprotection by NH3/MeOH results in the desired nucleosides (1a-d, 2a-d) formation.

Guanine↗
PubMed1990

[Characteristics of kinetics of phospholipid hydrolysis by phospholipase C from Bacillus cereus. Hydrolysis of phosphatidylcholine in the presence of deoxycholate].

Using dynamic light scattering and 31P-NMR spectroscopy methods, the reaction of solubilization of phosphatidylcholine by the ionic detergent, sodium deoxycholate, in aqueous solutions was studied. The kinetics of phosphatidylchodine hydrolysis by phospholipase C from B. cereus depending on the size and structural organization of substrate aggregates was investigated. No phosphatidylcholine hydrolysis was observed in the case of lamellar organization of the substrate, the size of lamellas not exceeding 2000-5000 A. The substrate hydrolysis rate within mixed micelles was controlled by the accessibility of the substrate on the surface of micellar aggregates. There was a decrease in the phosphatidylcholine hydrolysis rate at high detergent concentrations in the system. It was concluded that such a decrease in the hydrolysis rate can be due to two reasons, i) the decrease in mixed micelle size with a simultaneous decrease of surface concentration of the substrate, and, ii) the formation of "pure" detergent micelles capable to adsorb the enzyme by decreasing the "effective" concentration of phospholipase C.

Bacillus cereus↗
PubMed1990

[Lipids in drugs].

Data on the use of phospho- and glycolipids in drugs with various action targets are analysed. The issues include the use of lipids in parenteral emulsions. Essentiale-type++ preparations, and lipid adjuvants. Special emphasis is given to the transport and reconstructive functions of lipids. The drug-contained lipids were found to have a high biological activity, no allergy-inducing reactions, and a high biological degradability. The analysed evidence confirms the expediency of using drugs containing lipids of different chemical structures for medicinal purposes.

Drug Carriers↗
PubMed1989

Synapsin I from human brain. Phosphorylation by Ca2+, phospholipid-dependent protein kinase.

Synapsin I has been isolated from human brain by a rapid and efficient purification technique, and its phosphorylation by human brain Ca2+, phospholipid-dependent protein kinase (protein kinase C) has been studied. The inhibitory effect of calmodulin on this process has been demonstrated. It is also found that non-esterified fatty acids and acidic phospholipids are inhibitory for synapsin I phosphorylation by Ca2+, calmodulin-dependent protein kinase II.

Brain↗
PubMed1989

[High performance liquid chromatography of phospholipids on modified silica gel].

A sensitive method for the separation of phospholipids by a HPLC procedure is described. The separation was carried out on a 30 cm prepacked column with aminopropyl bonded silica under isocratic conditions. The effective separation of major phospholipid classes was carried out for less than 5 min. These chromatographic conditions were used for analysis of natural phospholipid mixtures.

Chromatography, High Pressure Liquid↗
PubMed1989

[Isolation and study of some properties of Ca2+-phospholipid dependent phosphokinase].

A modified method for isolation of rat brain Ca2+, phospholipid-dependent protein kinase has been developed. This procedure enables the purification of the enzyme to a state close to a homogeneous one within 18 hours. The first purification step allows for the separation of two peaks of the Ca2+, phospholipid-dependent protein kinase activity; further purification results in a homogeneous enzyme with a Mr of 80 kDa. It was shown that the second peak of protein kinase is a mixture of two polypeptides with Mr of 80 and 74 kDa. The 74 kDa protein also possesses a catalytic activity and is either an isoform or a proteolytic fragment of the native enzyme. The enzyme activation by phosphatidylserine and phosphatidylinositol was studied. It was shown that in contrast to the phosphatidylserine effect, the dependence of the protein kinase activity on phosphatidylinositol concentration is described by two apparent activation constants, which may be suggestive of the existence of two lipid-binding sites in the enzyme molecule: the enzyme affinity for phosphatidylinositol is 4 times higher than for phosphatidylserine. The data obtained suggest that phosphatidylinositol is a physiological activator of Ca2+, phospholipid-dependent protein kinase.

Animals↗
PubMed1988

Diol lipids are activators of protein kinase C.

Diol lipids (dioleoyl- and dioctanoylethylene glycol) at relatively low concentrations (approximately 10 microM) were found to activate significantly protein kinase C in the presence of phosphatidylserine or phosphatidylinositol. Since diol lipids are widespread minor lipid constituents of many cells [(1974) Chem. Ind., 597-604], it has been suggested that they may be involved in the maintaining of basal protein kinase C activity in the absence of external stimuli.

Adenosine Triphosphate↗
PubMed1988

[Studies of complex lipids. Synthesis of ionophore derivatives of diphosphatidylglycerol (cardiolipin)].

Synthesis of cardiolipin analogues containing an ionophore residue in the fatty acid moiety is described. The ionophore, dibenzo-18-crown-6, has been incorporated into second position of the glycerol residue by acylating mono- and dilysocardiolipin with a modified fatty acid anhydride. Lyso-derivatives of cardiolipin have been prepared by enzymatic hydrolysis of beef heart cardiolipin by snake venom phospholipase A2 (Naja naja oxiana).

Acylation↗
PubMed1987

[Study of complex lipids. Synthesis of diphosphatidylglycerol (cardiolipin) with unsaturated fatty acid residues].

Diphosphatidylglycerol (cardiolipin) with different fatty acid residues has been synthesised by condensation of 1,2-diacyl-sn-glycero-3-phosphoric acid (obtained, e.g., by the cabbage phospholipase D cleavage of 1,2-dioleyl-sn-glycero-3-phosphocholine or egg phosphatidylcholine) with 2-O-tert-butyldimethylsilylglycerol in the presence of 2,4,6-triisopropylbenzenesulphonylchloride. The synthetic cardiolipins as unsonicated aqueous calcium-free dispersions were shown, by means of 31P NMR spectroscopy, to form aggregates of the bilayer structure.

Cardiolipins↗
PubMed1987

[Effect of gangliosides on the resistance of mice to the rabies virus].

The survival of animals has been studied after their infection with a mixture of rabies virus and gangliosides isolated from various organs. It has been found that virus incubation with a summarized fraction of cerebral gangliosides increased considerably the survival of animals. At the same time it was shown that gangliosides from cattle spleen and red blood cells taken in the same proportions as cerebral gangliosides, do not have any protective effect. The in vivo study of the antiviral ganglioside activity has been performed.

Animals↗
PubMed1985

[Action of phospholipids and gangliosides on tumor cell sensitivity to the cytostatic and membrane-toxic action of splenic effectors].

The authors attempted to study which parts of the lipid molecules are most responsible for an increase in the sensitivity of the tumor cell to the cytostatic and membrano-toxic action of natural spleen effectors. Use was made of different combinations of egg phosphatidylcholine, phosphatidylethanolamine, cardiolipin, dipalmitoyl phosphatidylcholine and a mixture of bovine brain gangliosides. Introduction of phosphatidylethanolamine into the membrane of tumor cells increased, that of phosphatidylcholine and cardiolipin did not change whereas introduction of a mixture of brain gangliosides reduced their sensitivity to spleen effectors. Introduction of brain gangliosides together with egg phosphatidylcholine into the membrane of the target cell increased whereas that together with dipalmitoyl phosphatidylcholine reduced its sensitivity to spleen effectors. It is concluded that the increase in the sensitivity of the tumor cell primarily depends on changes in the lipid template of its membrane, induced by unsaturated fatty acids of egg phosphatidylcholine, and to a less degree on the properties of carbohydrate heads of gangliosides.

Animals↗