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1.
A new tryptophan-containing peptide has been identified in the methanol extracts of the skin of Phyllomedusa rohdei. The primary structure proposed is the following: <Glu-Glu-Lys-Pro-Tyr-Trp-Pro-Pro-Pro-Ile-Tyr-Pro-Met-OH.  相似文献   

2.
Syntheses by solution methods of tryptophyllin-7 (H-Val-Pro-Pro-Leu-Gly-Trp-Met-OH), a heptapeptide isolated from skin extracts of Phyllomedusa rhodei, and its methyl ester and amide are reported. Preliminary biological results in rats seem to indicate a growth promoting activity for both the acid and the ester derivative.  相似文献   

3.
A novel tryptophyllin has been isolated from the methanol extracts of the skin of the South American frog Phyllomedusa rohdei. Its primary structure, as determined by chemical/enzymatic methods and by FAB mass spectrometry, is the following: Lys-Pro-Hyp-Ser-Trp-Ile-Pro-NH2. This basic tryptophyllin has been synthesized in solid phase, in order to allow its complete pharmacological characterization.  相似文献   

4.
Syntheses by solution methods of tryptophyllins -4 and -5 (TPH-4 and TPH-5), tetra- and pentapeptides isolated from the skin extracts of the South American frog Phyllomedusa rhodei, are reported. The incorporation of the Pro2-Pro3 sequence into pentapeptides and the use of flash chromatography for purification of intermediates and target compounds are discussed. Preliminary biological results seem to indicate a growth-promoting activity for this peptide family.  相似文献   

5.
Tryptophyllins (TPH's) are members of a new family of amphibian skin peptides containing in their structures a tryptophyl residue. In this paper we describe the identification of tetra-, penta-, and heptapeptides occurring in the 70% ethanol eluates from alkaline alumina columns of skin extracts of Phyllomedusa rhodei.  相似文献   

6.
A new conspicuous set of peptides has been isolated from the skin of Phyllomedusa rhodei, a South American frog. All these peptides contain a tryptophyl residue, which justifies the suggested denomination of tryptophyllins (TPH). On the basis of their chain length, they were classified as TPH-4, TPH-5, etc. The peptides, described in this paper, have been isolated from the 95% ethanol eluate from an alumina column. They are tetra- and pentapeptide amides showing the characteristic sequences <Glu-Pro-Trp-Xxx (Xxx = Val, Met) and Phe-Pro-Pro-Trp-Xxx (Xxx = Val, Leu, Met), respectively.  相似文献   

7.
8.
A protected tridecapeptide, representing a new peptide corresponding to residues 56–68 of the VH domain in the mouse M603 myeloma protein, has been prepared by solid phase peptide synthesis. The protected tridecapeptide was prepared using the photolabile 4-bromomethyl-(3-nitro)-benzamidomethyl-resin and the multidetachable 2-[4-bromomethyl)phenylacetoxy] propionyl-resin as solid supports. The synthetic protocol and protecting groups were the same for both syntheses. The protected tridecapeptide was removed photolytically from both supports and the sequence integrity was determined by preview analysis using the solid phase Edman degradation procedure. The protected tridecapeptide-OMPA was purified to homogeneity by DMF/H2O precipitation and LH-60 chromatography. The purity of the protected peptide was further demonstrated by high pressure liquid chromatography on the free peptide after HF deprotection. The protected tridecapeptide was reattached to 4-bromomethyl-(3-nitro)-benzamidomethyl-resin to give the photolabile Boc-(protected) peptidyl-4 - oxymethyl - (3 - nitro) benzamidomethyl - resin in 25% yield. The protected tridecapeptide-oxymethylphenylacetic acid derivative was reattached to aminomethyl-resin to give Boc -(protected)peptidyl-2-[(4-oxymethyl)phenyl]acet-amidomethyl-resin in 45% yield and to 2-bromopropionyl-resin generating the multidetachable Boc - (protected)peptidyl - 2 - [(4 - oxymethyl) phenylacetoxy] propionyl-resin in 80% yield. The reactivity of these reattached peptides was demonstrated by the quantitative coupling of Boc-leucine to the protected peptide-resin. The advantages and disadvantages of the different resins with respect to solid phase fragment synthesis are discussed.  相似文献   

9.
A novel cyclic GRF analog, cyclo(Asp8-Lys12)-[Asp8,Ala15]-GRF(1-29)-NH2, i.e. cyclo8.12[Asp8,Ala15]-GRF(1-29)-NH2, was synthesized by the solid phase procedure and found to retain significant biological activity. Solid phase cyclization of Asp8 to Lys12 proceeded rapidly (~2h) using the BOP reagent. Substitution of Ala12 with d -Ala2 and/or NH2-terminal replacement (desNH2-Tyr1 or N-MeTyr1) in the cyclo8.12[Asp8,Ala15]-GRF(1-29)-NH2 system resulted in highly potent analogs that were also active in vivo. Conformational analysis (circular dichroism and molecular dynamics calculations based on NOE-derived distance constraints) demonstrated that cyclo8.12[Asp8,Ala15]-GRF(1-29)-NH2 contains a long α-helical segment even in aqueous solution. A series of cyclo8.12 stereoisomers containing d -Asp8 and/or d -Lys12 were prepared and also found to be highly potent and to retain significant α-helical conformation. The high biological activity of cyclo8.12[N-MeTyr1,d -Ala2,Asp8,Ala15]-GRF(1-29)-NH2 may be explained on the basis of retention of a preferred bioactive conformation.  相似文献   

10.
A synthesis of thymosin α11, a new 35 amino acid thymic peptide structurally related to thymosin α1 (J. Caldarella, G.J. Goodall, A.M. Felix, E.P. Heimer, S.B. Salvin & B.L. Horecker (1983) Proc. Natl. Acad. Sci US 80, 7424–7427), is reported. The synthesis was accomplished by the solid phase method employing the 4-(aminoacyloxymethyl) phenylacetamidomethyl(Pam)-copoly(styrene-1% divinylbenzene) resin. The synthetic material was purified by preparative high pressure liquid chromatography and was found to be equivalent to the natural compound in its chemical properties.  相似文献   

11.
We studied the effect of partial retro-inverso modification of selected peptide bonds of dermorphin (H-Tyr-d -Ala-Phe-Gly-Tyr-Pro-Ser-NH2. The modifications concern two consecutive peptide bonds (Phe3-Cly4-Tyr5, I) or a single one (Gly4-Tyr5-, II or Phe3-Gly4, III). All pseudoheptapeptides showed low opioid activity in the in vitro and in vivo tests. Compound III has a biological potency comparable to that of morphine but only 2–5% of original dermorphin when tested in guinea pig ileum preparation and in mice tail-flick assay after intra-cerebro or subcutaneous administration.  相似文献   

12.
Six peptides with amino acid sequences of human histocompatibility Class II membrane glycoproteins were synthesized by conventional solution methods. Five peptides were prepared by stepwise procedures from the carboxyterminus. The sixth was synthesized by fragment condensation (5 + 10 coupling). Antibodies to synthetic peptides were then used to locate exposed and buried regions in the membrane glycoproteins.  相似文献   

13.
Peptide sequences B-X-B (B = Arg and/or Lys; X = Glu or Asp) are of considerable interest because of their possible interactions with ribosomal RNA. The syntheses of various protected peptides with the sequence Ala-B-X-B-Ala (X = Glu or Ala) and [Arg]n-Pro (n = 1–3) are described. They are carried out in solution according to the conventional peptide synthesis method. The carbobenzoxy group is used for Nα-protection and the methyl group for the protection of the terminal carboxyl group. The side chains of Lys and Glu are respectively blocked with the tert.-butyloxycarbonyl and the tertiary butyl group and the guanidinic function of arginine with the NO2-group. The intermediate peptides are purified either by extraction or by size exclusion chromatography. A specially adapted strategy of peptide synthesis allows removal of the amino terminal Cbo-group at the end of the synthesis and introduction of an acryloyl group. By radical copolymerization with cross-linking agents these acryloyl derivatives can be transferred into insoluble peptide gels suitable for affinity chromatography and for investigating peptide-oligonucleotide interactions. The isolation of the unprotected peptides Arg-Arg-Arg-Pro, Ala-Arg-Glu-Arg-Ala, Ala-Arg-Glu-Lys-Ala, Ala-Arg-Ala-Lys-Ala, Ala-Lys-Glu-Lys-Ala and their characterization using amino acid analysis, electrophoresis, and FAB-mass spectrometry is also reported.  相似文献   

14.
Synthesis of the carbohydrate-free heptadecapeptide corresponding to the amino acid sequence of vespulakinin 1 was achieved by the continuous flow solid phase procedure on 4-hydroxymethyl-phenoxyacetyl-norleucyl derivatized Kieselguhr-supported polydimethylacrylamide resin, as well as by a combination of solid phase and solution syntheses. Preformed Fmoc-amino acid symmetrical anhydrides (Boc derivative for the N-terminal residue) were used for amine acylation in the continuous flow method. Serine and threonine were side chain protected as tert.-butyl ethers and the 4-methoxy-2, 3, 6,-trimethyl-benzenesulfonyl group was used for masking the guanidino function of arginine residues. After cleavage from the resin the final peptide was purified by ion exchange chromatography and characterized by amino acid analysis, high voltage electrophoresis, and RP-HPLC analysis. Alternatively, the protected N-terminal octapeptide, Fmoc-Thr(But)-Ala-Thr(But)-Thr(But)-Arg(Mtr)-Arg-(Mtr)-Arg(Mtr)-Gly-OH was prepared on 4-hydroxymethyl-3-methoxyphenoxyacetyl-norleucyl derivatized Kieselguhr-supported polydimethylacrylamide resin and the C-terminal nonapeptide H-Arg(NO2)-Pro-Pro-Gly-Phe-Ser-Pro-Phe-Arg-(NO2)-OBzl was synthesized in solution through the fragment condensation method. The two fragments were coupled by the DCC-HOBt procedure and the resulting heptadecapeptide was deblocked and purified. The conformational features of the synthesized peptides are reported. Preliminary pharmacological experiments indicated that carbohydrate-free vespulakinin 1 is more potent than bradykinin in lowering rat blood pressure.  相似文献   

15.
New analogues of head activator were produced for receptor and radioimmunoassay studies. The precursor molecules [(4′-I)Phe11] head activator and [Tyr11] head activator were synthesised for catalytic tritiation and iodination, respectively. With the tracer [(3,5-125 I2)Tyr11] head activator the sensitivity range of the radioimmunoassay was 5–100 fmol.  相似文献   

16.
Human salivary secretions are supersaturated with respect to basic calcium phosphates but spontaneous precipitation of these salts from saliva, or surface-induced precipitation of calcium phosphates onto dental enamel, does not normally occur. This unexpected stability has been attributed to the inhibitory activities of two kinds of salivary phosphoproteins: statherin and the acidic, proline-rich phosphoproteins (PRP). Investigation of the structure-function relationships of statherin, the most potent inhibitor of primary (spontaneous) and secondary (seeded) precipitation of calcium phosphate salts in human saliva has been limited to studies of peptide segments obtained from the native peptide by specific proteolysis. Solid phase peptide synthesis (SPPS) is a useful and potentially more flexible alternative. Phosphoserine residues (positions 2 & 3) play critically important roles in the precipitation-inhibition activities of statherin, but SPP synthesis of these phosphorylated peptides is precluded because of the instability of phosphoserine residues in the presence of HF. Thus, this peptide was synthesized by solution-phase methods. The dipeptide possessed substantial inhibitory activity in assays for inhibition of both primary and secondary precipitation of calcium phosphate salts, but was not as active as either N-terminal tryptic hexapeptide of statherin or intact statherin. Syntheses of other model phosphorylated peptides are underway to expand the structure-function relationships.  相似文献   

17.
H-Tyr-D-Ala-Phe-Gly-Tyr-Pro-Ser-NH2 (demorphin), an opiate-like peptide, and tri-, tetra-, penta- and hexapeptide-amide analogs, were synthesized by conventional methods in solution, to determine the minimum peptide chain-length, required for analgesic activity.  相似文献   

18.
We have investigated the structure-activity relationship of a series of new synthetic RGD analogs and their potential use as specific platelet aggregation inhibitors. Twelve short linear peptides showed high potency to inhibit aggregation in ADP-stimulated dog platelets. In order to assess the selectivity of these analogs towards platelet integrin GPIIb-IIIa, a new cell adhesion inhibition system was devised which was able to discriminate between the two closely related β3-integrins of the vasculature, GPIIb-IIIa (αIIbβ3), present in platelets, and the vitronectin receptor (αvβ3), expressed in endothelial cells and platelets. As reported for other peptides by Scarborough et. al. (1993, J. Biol. Chem. 2 68 , 1066), the analogs containing lysine instead of arginine in position 1 showed increased selectivity towards GPIIb-IIIa. One of them, in which the piperidine carboxylic group was attached to the N-terminus of KGDW, not only strongly inhibited platelet aggregation, but also selectively abolished cell adhesion mediated by GPIIb-IIIa without effect on the vitronectin receptor.  相似文献   

19.
3H‐Sch 58235 was prepared at a specific activity of 29.1 Ci/mmol by Ir(COD)(Cy3P)PyPF6 catalysed exchange with tritium gas. 14C‐Sch 58235 was prepared in three steps from p‐hydroxy[ring‐U‐14C]benzaldehyde with an overall radiochemical yield of 21%. 13C6‐Sch 58235 was similarly prepared in three steps from p‐hydroxy[ring‐U‐13C6]benzaldehyde in an overall yield of 41%. Copyright © 2002 John Wiley & Sons, Ltd.  相似文献   

20.
Sequential poly(Arg-Thr-Lys-Pro) consisting mainly of the repeat of tuftsin Thr-Lys-Pro-Arg was synthesized by condensing the p-nitrophenyl ester of Arg(HCI)-Thr-Lys-(2-CI-Z)-Pro in the presence of HOBt . Two haptenic sequences of the Pre-S region of hepatitis B virus antigen (10–26 and 39–55) were prepared by solid phase and coupled to polytuftsin via glutaraldehyde. The peptides, either free or coupled to polytuftsin, were administrated to mice and the antisera were assayed by ELISA . Coupling the peptides to the polypeptide significantly improved the anti-peptide antibody titer in Freund complete adjuvant or in NaCI 0.9%. Cross-reaction between antibodies induced by the peptides and the native protein was also improved. Polytuftsin alone is very poorly immunogenic.  相似文献   

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