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1.
Dolotov OV Zolotarev IuA Dorokhova EM Andreeva LA Alfeeva LIu Grivennikov IA Miasoedov NF 《Bioorganicheskaia khimiia》2004,30(3):241-246
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. 相似文献
2.
Zolotarev IuA Dadaian AK Dolotov OV Kozik VS Kost NV Sokolov OIu Dorokhova EM Meshavkin VK Inozemtseva LS Gabaeva MV Andreeva LA Alfeeva LIu Pavlov TS Badmaeva KE Badmaeva SE Bakaeva ZV Kopylova GN Samonina GE Vas'kovskiĭ BV Grivennikov IA Zozulia AA Miasoedov NF 《Bioorganicheskaia khimiia》2006,32(2):183-191
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. 相似文献
3.
4.
Yu. A. Zolotarev A. K. Dadayan O. V. Dolotov V. S. Kozik N. V. Kost O. Yu. Sokolov E. M. Dorokhova V. K. Meshavkin L. S. Inozemtseva M. V. Gabaeva L. A. Andreeva L. Yu. Alfeeva T. S. Pavlov K. E. Badmaeva S. E. Badmaeva Z. V. Bakaeva G. N. Kopylova G. E. Samonina B. V. Vaskovsky I. A. Grivennikov A. A. Zozulya N. F. Myasoedov 《Russian Journal of Bioorganic Chemistry》2006,32(2):166-173
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 μg scale of biological samples both in vitro and in vivo. 相似文献
5.
TÜNDE TÓTH OTTÓ ZSIROS MIHÁLY KIS GYŐZŐ GARAB LÁSZLÓ KOVÁCS 《Plant, cell & environment》2012,35(12):2075-2086
Despite intense research, the mechanism of Cd2+ toxicity on photosynthesis is still elusive because of the multiplicity of the inhibitory effects and different barriers in plants. The quick Cd2+ uptake in Synechocystis PCC 6803 permits the direct interaction of cadmium with the photosynthetic machinery and allows the distinction between primary and secondary effects. We show that the CO2‐dependent electron transport is rapidly inhibited upon exposing the cells to 40 µm Cd2+ (50% inhibition in ~15 min). However, during this time we observe only symptoms of photosystem I acceptor side limitation and a build of an excitation pressure on the reaction centres, as indicated by light‐induced P700 redox transients, O2 polarography and changes in chlorophyll a fluorescence parameters. Inhibitory effects on photosystem II electron transport and the degradation of the reaction centre protein D1 can only be observed after several hours, and only in the light, as revealed by chlorophyll a fluorescence transients, thermoluminescence and immunoblotting. Despite the marked differences in the manifestations of these short‐ and long‐term effects, they exhibit virtually the same Cd2+ concentration dependence. These data strongly suggest a cascade mechanism of the toxic effect, with a primary effect in the dark reactions. 相似文献
6.
PETER BOGNER DENYS N. WHEATLEY CSABA BORBLY ATTILA MISETA 《Cell biology international》1996,20(11):741-749
Exchange of erythrocyte intracellular (i/c) K+for extracellular (e/c) Na+in human erythrocytes treated with sub-CMC concentrations of the non-ionic detergent Brij 58 can be stopped by reincubation in serum or albumin containing solutions. The progressive equilibration of the K+contents of detergent-treated human erythrocytes with the incubation medium was reversed by an albumin-mediated withdrawal of detergent molecules from the cell. Re-establishment of near normal [K+] in terms of K+/kg water proceeds in two ways: (i) a metabolism-dependent net accumulation of K+ions; and (ii) a metabolism-independent shrinkage of erythrocytes, this being the more significant factor. 相似文献
7.
Shevchenko KV Nagaev IIu Alfeeva LIu Andreeva LA Kamenskiĭ AA Levitskaia NG Shevchenko VP Grivennikov IA Miasoedov NF 《Bioorganicheskaia khimiia》2006,32(1):64-70
The radioactive peptide analogue Semax corresponding to the ACTH(4-10) sequence (Met-Glu-His-Phe-Pro-Gly-Pro) with a molar radioactivity of 56 Ci/mmol labeled with tritium at the C-terminal Pro was prepared. The labeled peptide was used for studying the kinetics of Semax penetration into rat brain and blood after its intranasal administration (50 microg/kg, 20 microl of solution) to nonbred white rats of body mass 200-250 g. It was demonstrated that 0.093% of the total introduced radioactivity per gram can be found in the rat brain 2 min after the administration, 80% of this radioactivity belonged to Semax, and the rest, to its metabolites. The peptide undergoes rapid enzymatic degradation, with the tripeptide Pro-Gly-Pro prevailing in biological samples relative to the total content of Semax and its metabolites. 相似文献
8.
18S rRNA data indicate that Aschelminthes are polyphyletic in origin and consist of at least three distinct clades 总被引:7,自引:1,他引:6
Winnepenninckx B; Backeljau T; Mackey LY; Brooks JM; De Wachter R; Kumar S; Garey JR 《Molecular biology and evolution》1995,12(6):1132-1137
The Aschelminthes is a collection of at least eight animal phyla,
historically grouped together because the absence of a true body cavity was
perceived as a pseudocoelom. Analyses of 18S rRNA sequences from six
Aschelminth phyla (including four previously unpublished sequences) support
polyphyly for the Aschelminthes. At least three distinct groups of
Aschelminthes were detected: the Priapulida among the protostomes, the
Rotifera-Acanthocephala as a sister group to the protostomes, and the
Nematoda as a basal group to the triploblastic Eumetazoa.
相似文献
9.
Chimpanzee fetal G gamma and A gamma globin gene nucleotide sequences provide further evidence of gene conversions in hominine evolution 总被引:5,自引:0,他引:5
The fetal globin genes G gamma and A gamma from one chromosome of a
chimpanzee (Pan troglodytes) were sequenced and found to be closely similar
to the corresponding genes of man and the gorilla. These genes contain
identical promoter and termination signals and have exons 1 and 2 separated
by the conserved short intron 1 (122 bp) and exons 2 and 3 separated by the
more rapidly evolving, larger intron 2 (893 bp and 887 bp in chimpanzee G
gamma and A gamma, respectively). Each intron 2 has a stretch of simple
sequence DNA (TG)n serving possibly as a "hot spot" for recombination. The
two chimpanzee genes encode polypeptide chains that differ only at position
136 (glycine in G gamma and alanine in A gamma) and that are identical to
the corresponding human chains, which have aspartic acid at position 73 and
lysine at 104 in contrast to glycine and arginine at these respective
positions of the gorilla A gamma chain. Phylogenetic analysis by the
parsimony method revealed four silent (synonymous) base substitutions in
evolutionary descent of the chimpanzee G gamma and A gamma codons and none
in the human and gorilla codons. These Homininae (Pan, Homo, Gorilla)
coding sequences evolved at one-tenth the average mammalian rate for
nonsynonymous and one-fourth that for synonymous substitutions. Three
sequence regions that were affected by gene conversions between chimpanzee
G gamma and A gamma loci were identified: one extended 3' of the hot spot
with G gamma replaced by the A gamma sequence, another extended 5' of the
hot spot with A gamma replaced by G gamma, and the third conversion
extended from the 5' flanking to the 5' end of intron 2, with G gamma
replaced here by the A gamma sequence. A conversion similar to this third
one has occurred independently in the descent of the gorilla genes. The
four previously identified conversions, labeled C1-C4 (Scott et al. 1984),
were substantiated with the addition of the chimpanzee genes to our
analysis (C1 being shared by all three hominines and C2, C3, and C4 being
found only in humans). Thus, the fetal genes from all three of these
hominine species have been active in gene conversions during the descent of
each species.
相似文献
10.
Broccardo M Usenko AB Uranova MG Guzevatykh LS Kamensky AA Andreeva LA Alfeeva LY Myasoedov NF Giannini E Improta G Emel'yanova TG 《Peptides》2003,24(3):419-428
To study the effects of inducing stereo-chemical modifications in the structure of dermorphin (DM) so as to improve its mu-opioid receptor affinity and its resistance to C-terminal enzymatic degradation, in the Institute of Molecular Genetics of Moscow, we synthesized a new DM analogue ([DPro(6)]DM) and analyzed the changes induced in the biological activities of DM by substituting the Pro(6) residue with DPro(6). We compared the activity of the new DM analogue and DM in in vitro assays and in in vivo tests of analgesia, thermoregulation, heart rate recordings, and gastrointestinal motility in rats. In the in vitro tests, guinea pig ileum (GPI) and mouse vas deferens (MVD), although the opioid activities of [DPro(6)]DM indicated that the peptide was always less potent than DM, its lower IC(50) ratios (mu/delta) showed that it had higher mu-opioid receptor selectivity. In the in vivo analgesic test, [DPro(6)]DM, when injected intraperitoneally (i.p.) (0.5-5 and 10mg/kg) in rats, had the same antinociceptive efficacy as DM and when injected intranasally (i.n.) (0.005 and 0.02 mg/kg) it induced a more stable and long-lasting analgesia than DM (the AUC was about 91% higher for [DPro(6)]DM than for DM). Moreover, these data confirm that the intranasal route is advantageous for peripheral drug administration. In the heart rate study, [DPro(6)]DM and DM (0.5mg/kg, i.p.), induced a similar, weak bradycardia. The only difference was that [DPro(6)]DM induced a longer-lasting effect than DM. Conversely, in body temperature regulation [DPro(6)]DM induced weaker inhibitory activity than DM (56% of the DM-induced response); it did so only in a cold environment and at the maximal used dose (0.5mg/kg, i.p.) without inducing vasomotor effects. In the gastrointestinal study, [DPro(6)]DM and DM (0.005, 0.05, and 0.5mg/kg, i.p.) significantly slowed upper gastrointestinal transit of a charcoal meal and inhibited colonic propulsion. Comparison of the ED(50) values of [DPro(6)]DM (0.03 mg/kg) and DM (0.009 mg/kg) showed that the DM analogue was about three times less potent than DM in slowing gastrointestinal and colonic transit. In conclusion, all these data overall suggest that structural maneuvering in the Pro(6)-residue of the DM molecule changes its affinity for mu-opioid receptor subtypes and confirms the usefulness of experimental studies involving structural modifications in obtaining new therapeutic agents. 相似文献