Biomedical subjects

Iu A Zolotarev

Publications and source records attributed to Iu A Zolotarev.

17 recordsLinked to original sources

PubMed2000

[Biologically active fragment of the differentiation factor from HL-60 cell line. Identification and properties].

Six-membered peptide fragment TGENHR (HLDF-6) was identified in the HL-60 cell culture of human promyelocyte leukemia treated with retinoic acid when studying the differentiation factor HLDF of this cell line. HLDF-6 retains the ability of the full-size factor to induce the differentiation and arrest the proliferation of the starting HL-60 cells. It was shown that the synthetic peptide HLDF-6 has no specific receptors on the surface of the HL-60 cells but can affect the binding of interleukin IL-1 beta, a cytokine involved in proliferation, to the cell surface. It was found on a model of transplantable NSO myeloma that HLDF-6 has an antitumor activity.

Animals↗

PubMed2000

[Solid phase catalytic hydrogen isotope exchange in dalargin].

A [3H]Dalargin preparation with a molar radioactivity of 52 Ci/mmol was obtained by the high temperature solid-state catalytic isotope exchange (HSCIE) of tritium for hydrogen at 150 degrees C. This tritium-labeled peptide was shown to completely retain its biological activity in the test of binding to opioid receptors from rat brain. The dissociation constant of the Dalargin-opioid receptor complex was found to be 4.3 nM. The dependencies of the chemical yield and the molar radioactivity on the reaction time and temperature of HSCIE were determined. The activation energy of the HSCIE reaction for the peptide was calculated to be 32 kcal/mol. The amino acid analysis showed that tritium is distributed between all the amino acid residues of [3H]Dalargin at the HSCIE reaction, with the temperature growth significantly increasing the total tritium incorporation and, especially, enhancing the radioactivity incorporation into aromatic residues.

Animals↗

PubMed2000

[Study of solid-phase catalytic isotopic exchange of hydrogen in alpha-conotoxin G1 under the effect of spillover-tritium].

Tritium-labeled alpha-conotoxin G1 with a molar radioactivity of 35 Ci/mmol and full biological activity (according to the binding to nicotinic acetylcholine receptor) was obtained by the high-temperature solid-state catalytic isotope exchange (HSCIE). The tritium distribution in the molecule of alpha-conotoxin G1 was revealed by 3H NMR spectroscopy. Tritium was found in all amino acid residues except for the Asn4-Pro5-Ala6 fragment. The data on the comparative reactivity of C-H bonds, the ab initio quantum-chemical calculation of the hydrogen exchange reaction, and the information on the spatial structures of alpha-conotoxin G1 in solution and in crystal state allowed us to establish that the reactivity of H atoms may be increased by their interaction with the electron donor O and N atoms at the transition state of the HSCIE reaction. A decrease in the rate of the HSCIE reaction could be caused by both a poor spatial accessibility of C-H bonds and a limited mobility of the peptide fragment containing these bonds.

Amino Acid Sequence↗

PubMed1990

[Analysis of highly tritium-labeled alanine using 3H- and 1H-NMR].

A method has been developed for the analysis of deuterium oxide solutions of tritiated alanine eight-component isotopic mixtures by using high resolution 3H and 1H NMR spectra at frequencies 266.8 and 500.13 MHc, respectively. Approaches have been worked out for the determination of qualitative composition of the mixtures and spectral parameters.

Alanine↗

PubMed1990

[Analysis of tritium-labeled glycine and alanine using 3H-NMR].

A method for analysis of three-component isotopic mixtures of tritium-labelled glycine and alanine in D2O solutions has been developed on the basis of high resolution 3H NMR spectra at 266.8 MHz. Determined were composition of the mixtures in molar per cent, as well as geminal and vicinal coupling constants (2JGly3H,H = -16.4 +/- 0.2 Hz; 2JAla3H,H = -14.0 +/- 0.5 Hz; 3JAla3H,H = 7.6 +/- 0.2 Hz) and isotopic shifts (0.21 +/- 0.001 ppm for glycine; 0.026 +/- 0.001 ppm for alanine).

Alanine↗

PubMedDate not supplied

[Solid phase isotope exchange with spillover hydrogen in amino acids, peptides, and proteins].

We summarize here information on the theoretical and experimental study of high-temperature (150-200 degrees C) solid phase catalytic isotope exchange (HTSPCIE) carried out with amino acids, peptides, and proteins under the action of spillover hydrogen. Main specific features of the HTSPCIE reaction, its mechanism, and its use for studying spatial interactions in polypeptides are discussed. A virtually complete absence of racemization makes this reaction a valuable preparative method. The main regularities of the HTSPCIE reaction with the participation of spillover tritium have been revealed in the case of peptides and proteins, and the dependence of reactivity of peptide fragments on the spatial organization of their molecules has been studied. An important peculiarity of this reaction is that HTSPCIE proceeds at 150-200 degrees C with a high degree of chirality retention in amino acids and peptides. This is provided by its reaction mechanism, which consists in a synchronous one-center substitution at the saturated carbon atom characterized by the formation of pentacoordinated carbon and a three-center bond between the carbon and the incoming and outgoing hydrogen atoms.

Amino Acids↗

PubMedDate not supplied

[Leu-enkephalin homogeneously labeled with tritium in studying the Selank inhibiting effect on the enkephalin-degrading enzymes of human plasma].

A method of analysis of enkephalinase activity in blood plasma based on the application of Leu-enkephalin generally labeled with tritium at all its amino acid residues was developed. The method allows the simultaneous estimation of activity of several peptidases in microquantities of tissues. [G-3H]Leu-enkephalin was prepared by the method of solid phase catalytic isotope exchange (120 Ci/mmol) and subjected to proteolysis by the treatment with blood plasma. The resulting radioactive metabolites were separated by HPLC in the presence of the mixture of unlabeled fragments of Leu-enkephalin as internal standards. It was shown that aminopeptidases, dipeptidylaminopeptidases, and dipeptidylcarboxypeptidases respond for approximately 80%, 2%, and 10% of the total enzymatic activity, respectively. The new pathway of degradation of Leu-enkephalin by carboxypeptidase that provides for approximately 6% of the total enkephalin-degrading activity was discovered. Bestatin was shown to predominantly inhibit aminopeptidases and carboxypeptidases, whereas Selank is more specific for carboxypeptidases and dicarboxypeptidases. The English version of the paper: Russian Journal of Bioorganic Chemistry, 2004, vol. 30, no. 3; see also http://www.maik.ru.

Aminopeptidases↗

PubMedDate not supplied

[The binding of Semax, ACTH 4-10 heptapeptide, to plasma membranes of the rat forebrain basal nuclei and its biodegradation].

The binding characteristics of the peptide Semax (Met-Glu-His-Phe-Pro-Gly-Pro) to plasma membranes of basal nuclei of the rat forebrain and the dynamics of its degradation during its incubation with these membranes were studied. Binding of the homogeneously labeled [G-3H]Semax was shown to be time-dependent, specific, and reversible. Specific binding of the heptapeptide depended on calcium ions and was characterized by the dissociation constant of the ligand-receptor complex Kd = 2.41 +/- 1.02 x 10(-9) M and by the concentration of binding sites Bmax = 33.5 +/- 7.9 x 10(-15) mol/mg of protein. A method of studying Semax biodegradation in the presence of plasma membranes of rat brain was developed. It is based on the use of the peptide homogeneously labeled with tritium and on an HPLC analysis with UV detection at 220 and 254 nm of the peptide fragments formed. The half-life of Semax in the presence of the plasma membranes was demonstrated to be longer than 1 h. Dipeptidylaminopeptidases are considered to be the main enzymes responsible for its biodegradation; they successively cleave Semax to the HFPGP pentapeptide and the PGP tripeptide. The English version of the paper: Russian Journal of Bioorganic Chemistry, 2004, vol. 30, no. 3; see also http://www.maik.ru.

Adrenocorticotropic Hormone↗

PubMedDate not supplied

[Stress-protective effect of the synthetic ACTH-like peptide leucocorticotropin].

We found that the tritium-labeled synthetic ACTH-like octapeptide leucocorticotropin corresponding to the 81-88 sequence of the precursor of human interleukin-1alpha ([3H]GKVLKKRR) is bound by the ACTH receptor of rat adrenal cortex with a high affinity and specificity (Kd 2.2 +/- 0.1 nM). This peptide was shown to exert no effect on the adenylate cyclase activity of the membranes of rat adrenal cortex in the concentration range from 1 to 1000 nM. Leucocorticotropin administration three times at doses of 10-20 microg/animal did not change the level of hydroxycorticosteroids (11-HOCS) in the rat adrenal glands in the absence of temperature action. At the same time, the peptide abolishes (at a dose of 20 microg/animal, three times) or significantly decreases (at a dose of 10 microg/animal, three times) the dramatic increase in the 11-HOCS content in the adrenal glands occurring in the case of cold or heat shock. Thus, leucocorticotropin normalizes the 11-HOCS level in the rat adrenal cortex during stress. The stress-protective effect of the peptide is mediated through the ACTH receptor.

Administration, Intranasal↗

PubMedDate not supplied

[Comparative study of the distribution of 3[H]-himantane in the brain structures and the thymus of rats].

Dynamics of distribution of 3[H]-labeled himantane (N-(adamant-2-yl) hexamethyleneimine hydrochloride), a new drug possessing antiparkinsonian and immunostimulant activity, was monitored over a time period of 10 days after single injection (10 mg/kg, i.v.) in rats. It is show that himantane exhibits a selective affinity with respect to the tissues of striatum, where up to 10(-5) M of the radioactive drug equivalent is absorbed. This is significantly greater as compared to the relative amounts of drug in the whole brain, hippocampus, cerebellum, or thymus. The accumulation of radioactive himantane in striatum increased upon oral administration, which is indicative of the formation of drug metabolites possessing higher lipophilicity.

Adamantane↗

PubMedDate not supplied

[Effect of new peptide bioregulators livagen and epitalon on enkephalin-degrading enzymes in human serum].

The effect of new peptide bioregulators--Livagen (Lys-Glu-Asp-Ala) and Epitalon (Ala-Glu-Asp-Gly)--on endogenous opioid system was studied, particularly, their ability to change the activity of enkephalin-degrading enzymes from serum and interact with opioid receptors of the brain membrane fraction. Enkephalinase activity was assayed in vitro by the rate of 3H-Leu-enkephalin hydrolysis in the presence of the tested peptides. Livagen and Epitalon inhibited enkephalin-degrading enzymes from human serum. Livagen proved to be more efficient also as compared to well-known peptidase inhibitors such as puromycin, leupeptin, and D-PAM. The dose-inhibitory effect curves for Livagen and Epitalon were plotted; their IC50 equaled 20 and 500 microM, respectively. The interaction between the peptides and opioid receptors was estimated using a radioreceptor method with [3H][D-Ala2, D-Leu5]-enkephalin. No interaction was observed between the tested peptides and mu- or delta-opioid receptors of the membrane fraction from the rat brain.

Animals↗

PubMedDate not supplied

[Highly stable regulatory oligopeptides: experience and applications].

The most stable regulatory peptides (RP) including the new family of RP (glyprolines) and derivatives of hybrid peptide MEHFPGP are characterized. High ability of glyprolines to penetrate into the blood-stream through the gastrointestinal tract is demonstrated. Antiulcer, antithrombotic and antidiabetic activities of glyprolines were discovered in experiments on white rats. The activity of oligopeptides PGP, PG and GP is compared. Mechanisms of glycoprolines activities and feasibility of their administration with connective tissue food proteins are discussed. Thus, glyprolines are perspective drugs for treatment of gastric ulcer, correction of hemostasis and thrombosis suppression prepared for preclinical trial.

Adrenocorticotropic Hormone↗

PubMedDate not supplied

[Pharmacokinetics of glyprolines (PGP) upon intragastric administration].

The pharmacokinetics of glyprolines upon intragastric administration in rats was studied by monitoring the content of tritium-labeled PGP in the blood plasma and protein, in organs (for 5 h), and urine (for 8 h). The maximum radioactivity (2.25% of the introduced level) in the blood plasma was observed 15 min after administration of [3H]-PGP. Then, the radioactivity level gradually decreased, but even in 5 h it exceeded 1%. In contrast, the radioactivity of deposited protein gradually increased. The content of labeled PGP and its metabolites in organs was much lower than in the blood. The radioactivity 15 min after administration was as follows (%): intestine, 1.4; stomach, 0.1; liver, 0.09; brain, heart, and kidney, < 0.05; in 5 h, the radioactivity level was below 0.02% (except for intestine, where it was still greater than 0.1%). No labeled PGP or its metabolites were found in the urine during the 8-h period of observations. It is not excluded that glyprolines introduced with PGP are involved in the synthesis of new peptides and proteins, including collagen.

Animals↗

PubMedDate not supplied

[Rhythm of protein synthesis in cultures of hepatocytes from rats of different ages. Norm and effect of the peptide livagen].

The circumhoralian rhythm of protein synthesis was determined in a monolayer culture of hepatocytes from rats at the age of 1 to 24 months and weighing from 45 to 480 g, respectively. The peptide lyvagen (Lys-Glu-Asp-Ala) obtained by directed chemical synthesis on the basis of amino acid analysis of the liver polypeptide preparations increased the level of protein synthesis in the hepatocytes from rats of different ages; the highest effect was observed in the cells of old animals. In old rats, lyvagen increased the amplitude of protein synthesis fluctuations. The peptide epitalon (Ala-Glu-Asp-Gly) constructed on the basis of analysis of the epiphysis peptides did not change the intensity of protein synthesis in the cultured hepatocytes.

Age Factors↗

PubMedDate not supplied

[Evenly tritium-labeled peptides and their in vivo and in vitro biodegradation].

Biologically active peptides evenly labeled with tritium were used for studying the in vitro and in vivo biodegradation of the peptides. Tritium-labeled peptides with a specific radioactivity of 50-150 Ci/mmol were obtained by high temperature solid phase catalytic isotope exchange (HSCIE) with spillover tritium. The distribution of the isotope label among all amino acid residues of these peptides allows the simultaneous determination of practically all possible products of their enzymatic hydrolysis. The developed analytical method includes extraction of tritium-labeled peptides from organism tissues and chromatographic isolation of individual labeled peptides from the mixture of degradation products. The concentrations of a peptide under study and the products of its biodegradation were calculated from the results of liquid scintillation counting. This approach was used for studying the pathways of biodegradation of the heptapeptide TKPRPGP (Selank) and the tripeptide PGP in blood plasma. The pharmacokinetics of Selank, an anxiolytic peptide, was also studied in brain tissues using the intranasal in vivo administration of this peptide. The concentrations of labeled peptides were determined, and the pentapeptide TKPRP, tripeptide TKP, and dipeptides RP and GP were shown to be the major products of Selank biodegradation. The study of the biodegradation of the heptapeptide MEHFPGP (Semax) in the presence of nerve cells showed that the major products of its biodegradation are the pentapeptide HFPGP and tripeptide PGP. The enkephalinase activity of blood plasma was studied with the use of evenly tritium-labeled [Leu]enkephalin. A high inhibitory effect of Semax on blood plasma enkephalinases was shown to arise from its action on aminopeptidases. The method, based on the use of evenly tritium-labeled peptides, allows the determination of peptide concentrations and the activity of enzymes involved in their degradation on a tg scale of biological samples both in vitro and in vivo.

Adrenocorticotropic Hormone↗

PubMedDate not supplied

[Short peptide fragments with antiulcer activity from a collagen hydrolysate].

A peptide acidic hydrolysate of collagen (PHC) was obtained under conditions (4 N HCl) ensuring the predominant formation of short peptides, glyprolines. They were separated and their antiulcer activity was studied. Thirty individual peptides with molecular masses of 174-420 amu were isolated from the PHC by HPLC. The PHC was shown to predominantly contain 2- to 4-aa peptides, including PG, GP, and PGP. Experiments on rats demonstrated that, on intragastric administration at a dose of 1 mg/kg, PHC enhances the stability of the gastric mucosa to the action of ulcerogenic factors, such as ethanol and stress, and exhibits a protecting antiulcer effect. Even a lesser dose (0.1 mg/kg), which reduced ulcer area twofold, was effective in the stress model of ulcer formation. The intraperitoneal and intragastric administration of PHC at a dose of 1 mg/kg was found to exhibit a therapeutic effect in the acetate model of ulcer formation.

Animals↗

PubMedDate not supplied

[Reculatory fragments of collagen in gastric mucosa homeostasis].

The new glyproline family was distinguished from the regulatory peptides recently. It includes the simplest proline- and glycine-containing peptides: PG, GP, PGP, and respective peptides with hydroxylated proline residues. Glyproline's bioactivity covers many important systems of the body including suppression of some reaction in the blood coagulation and platelet aggregation and gastric mucosal maintenance. It was shown that PGP, PG and GP have a wide spectrum of antiulcer activity with respect to gastric mucosal damages of various aetiology. GHyp and HypGP show also antiulcer action. In vivo glyprolines being fragments of collagen may be generated during synthesis and catabolism of collagen. It is well known that approximately 10-60% of newly synthesized collagen degrade intracellularly with succeeding secretion of small peptides composed of less than 5 aminoacid residues out of cells. Different simplest proline and hydroxyproline fragments of glyprolines are revealed in various type of collagen: GP, GHyp, PG, PPG, PGP, PHypG., GPHyp, GPP, GPG, GHypP, HypGP. It is possible that these fragments may be also secreted out of cells during the stage of degradation of newly synthesized collagen. We showed that the intragastric (per oral) introduction of hydrolyzed gelatin, having 20 small peptide fragments, including PGP and HypGP, also increase gastric stability showing protective and therapeutic antiulcer effect. The corresponding receptors for glyprolines are not completely identified yet but it may be supposed that PGP, GP and other glyprolines interact with the same receptors with which the III type collagen is binding with platelet's receptors. It is supposed that octapeptide sequence KPGGluPGPK of collagen is rather important for binding with receptor. When this sequence in the structure of collagen's molecule binds with the receptor, platelet aggregation is induced. Free octapeptide blocks the receptor and inhibits platelet aggregations. Qualitatve characteristics of parameters of inhibition with intact octapeptide and glyproline, as well as the receptor's structure--that's our concern for the nearest future.

Animals↗