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Peptide Synthesis (peptide + synthesis)
Kinds of Peptide Synthesis Selected AbstractsA Fluorous Capping Strategy for Fmoc-Based Automated and Manual Solid-Phase Peptide SynthesisEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 4 2006Vittorio Montanari Abstract Just add water: Peptides synthesized by the use of standardized Fmoc protocols with commercial automated synthesizers can be purified from deletion products by simple centrifugation of aqueous solutions. The deletion products are capped with fluorous trivalent iodonium salts. At the end of the synthesis, the crude peptide is dissolved in water and centrifuged, and the deletion products precipitate leaving only the full length peptide in solution. Protocols for generalized use of this strategy are reported. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006) [source] N -Tetrachlorophthaloyl (TCP) Protection for Solid-Phase Peptide SynthesisEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 17 2004Esther Cros Abstract The N -tetrachlorophthaloyl-(TCP-)amino protecting group has been evaluated for use in solid-phase peptide synthesis. The TCP group was unaffected by exposure to either piperidine or N,N -diisopropylethylamine (DIEA), which suggests compatibility with both Fmoc and Boc solid-phase synthesis protocols. Quantitative TCP removal was achieved by treatment with hydrazine/DMF (3:17) at 35 °C for 30 min or with ethylenediamine/DMF (1:200) at 50 °C for 30 min. Several C-terminal peptide amides were synthesized successfully by following protocols that use hydrazine/DMF (3:17) at 40 °C for 1 h for repetitive deprotection. Treatment of TCP-amines with methylamine or with diamines did not give the corresponding amines (deprotected), but rather the appropriate N,N, -disubstituted tetrachlorophthalamides, which corresponds to a single ring-opening step. This observation was harnessed to prepare linear and macrocyclic peptide,arene hybrids based on the mild reaction of the parent TCP compound with 1,3-diaminopropane/DMF (1:49) at 25 °C for 5 min. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004) [source] Nonribosomal Peptide Synthesis in Schizosaccharomyces pombe and the Architectures of Ferrichrome-Type Siderophore Synthetases in FungiCHEMBIOCHEM, Issue 4 2006Torsten Schwecke Dr. Abstract A nonribosomal peptide synthetase (NRPS) in Schizosaccharomyces pombe, which possesses an unusual structure incorporating three adenylation domains, six thiolation domains and six condensation domains, has been shown to produce the cyclohexapeptide siderophore ferrichrome. One of the adenylation domains is truncated and contains a distorted key motif. Substrate-binding specificities of the remaining two domains were assigned by molecular modelling to glycine and to N -acetyl- N -hydroxy- L -ornithine. Hexapeptide siderophore synthetase genes of Magnaporthe grisea and Fusarium graminearum were both identified and analyzed with respect to substrate-binding sites, and the predicted product ferricrocin was identified in each. A comparative analysis of these synthetase systems, including those of the basidiomycete Ustilago maydis, the homobasidiomycete Omphalotus olearius and the ascomycetes Aspergillus nidulans, Aspergillus fumigatus, Fusarium graminearum, Cochliobolus heterostrophus, Neurospora crassa and Aureobasidium pullulans, revealed divergent domain compositions with respect to their number and positioning, although all produce similar products by iterative processes. A phylogenetic analysis of both NRPSs and associated L - N5 -ornithine monooxygenases revealed that ferrichrome-type siderophore biosynthesis has coevolved in fungi with varying in trans interactions of NRPS domains. [source] ChemInform Abstract: Novel N,S-Phenacyl Protecting Group and Its Application for Peptide Synthesis.CHEMINFORM, Issue 48 2008Guo Tang Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Peptide Synthesis in Room Temperature Ionic Liquids.CHEMINFORM, Issue 22 2004Helene Vallette Abstract For Abstract see ChemInform Abstract in Full Text. [source] Chiral Heterospirocyclic 2H-Azirin-3-amines as Synthons for 3-Amino-2,3,4,5-tetrahydrofuran-3-carboxylic Acid and Their Use in Peptide Synthesis.CHEMINFORM, Issue 39 2003Simon Stamm Abstract For Abstract see ChemInform Abstract in Full Text. [source] Design and Synthesis of a ,-Amino Phosphotyrosyl Mimetic Suitably Protected for Peptide Synthesis.CHEMINFORM, Issue 12 2003Kyeong Lee Abstract For Abstract see ChemInform Abstract in Full Text. [source] A Designed Well-Folded Monomeric Four-Helix Bundle Protein Prepared by Fmoc Solid-Phase Peptide Synthesis and Native Chemical Ligation,CHEMISTRY - A EUROPEAN JOURNAL, Issue 5 2006Gunnar T. Dolphin Dr. Abstract The design and total chemical synthesis of a monomeric native-like four-helix bundle protein is presented. The designed protein, GTD-Lig, consists of 90 amino acids and is based on the dimeric structure of the de novo designed helix-loop-helix GTD-43. GTD-Lig was prepared by the native chemical ligation strategy and the fragments (45 residues long) were synthesized by applying standard fluorenylmethoxycarbonyl (Fmoc) chemistry. The required peptide,thioester fragment was prepared by anchoring the free ,-carboxy group of Fmoc-Glu-allyl to the solid phase. After chain elongation the allyl moiety was orthogonally removed and the resulting carboxy group was functionalized with a glycine,thioester followed by standard trifluoroacetic acid (TFA) cleavage to produce the unprotected peptide,thioester. The structure of the synthetic protein was examined by far- and near-UV circular dichroism (CD), sedimentation equilibrium ultracentrifugation, and NMR and fluorescence spectroscopy. The spectroscopic methods show a highly helical and native-like monomeric protein consistent with the design. Heat-induced unfolding was studied by tryptophan absorbance and far-UV CD. The thermal unfolding of GTD-Lig occurs in two steps; a cooperative transition from the native state to an intermediate state and thereafter by noncooperative melting to the unfolded state. The intermediate exhibits the properties of a molten globule such as a retained native secondary structure and a compact hydrophobic core. The thermodynamics of GuHCl-induced unfolding were evaluated by far-UV CD monitoring and the unfolding exhibited a cooperative transition that is well-fitted by a two-state mechanism from the native to the unfolded state. GTD-Lig clearly shows the characteristics of a native protein with a well-defined structure and typical unfolding transitions. The design and synthesis presented herein is of general applicability for the construction of large monomeric proteins. [source] The Mercaptomethyl Group Facilitates an Efficient One-Pot Ligation at Xaa-Ser/Thr for (Glyco)peptide Synthesis,ANGEWANDTE CHEMIE, Issue 31 2010Hironobu Hojo Prof. Erleichterte Kupplung: Eine Mercaptomethylgruppe in der Seitenkette von Serin und Threonin erleichterte die native chemische Ligation an der Xaa-Ser/Thr-Position (siehe Schema; R=H, Me). Der intermediäre Thioester geht eine S-N-Acylverschiebung ein, und nach der Ligation wurde die Methylgruppe spontan abgespalten, wobei das Glycopeptid Contulakin-G und humanes Calcitonin erhalten wurden. [source] On choosing the right ether for peptide precipitation after acid cleavageJOURNAL OF PEPTIDE SCIENCE, Issue 3 2008Beatriz G. de La Torre Abstract Methyl tert -butyl ether (MTBE) and diethyl ether (DEE) tend to be regarded as interchangeable for the ,cold ether' workup concluding the final acidolytic cleavage and deprotection step of solid-phase peptide syntheses. However, the use of MTBE to precipitate peptides from strong acid solutions is shown to give rise to t -butyl alkylation byproducts, readily detectable by MALDI-TOF MS. The problem can attain undesirable dimensions in the cleavage of peptide resins containing high proportions of aromatic residues, particularly in peptide nucleic acid (PNA) syntheses. In those cases, DEE workup is advisable, as it consistently leads to cleaner products. Copyright © 2007 European Peptide Society and John Wiley & Sons, Ltd. [source] Synthesis, and Structural and Biological Studies of Efrapeptin C AnaloguesCHEMISTRY & BIODIVERSITY, Issue 6 2007Micha Jost Abstract A series of analogues of efrapeptin,C (1), with variations in the central tripeptide epitope (positions 6,8), were prepared by a combination of solid- and solution-phase peptide syntheses. The conformations of the modified compounds 2,6 were investigated by circular-dichroism (CD) spectroscopy to differentiate between 310 - and , -helical secondary structures. The inhibitory activities of the new compounds towards F1 -ATPase from E. coli were determined. The modified congeners 3,5 were less active by one order of magnitude compared to 1 (Ki 10,,M), and 6 was completely inactive. Our experiments demonstrate that the flexible, central tripeptide epitope, comprising positions 6,8 in 1, is crucial for molecular recognition, even slight sequence modifications being hardly tolerated. [source] N -(4-Nitrophenylsulfonyl)- and N -(Fluorenylmethoxycarbonyl)- N -ethyl Amino Acid Methyl Esters , A Practical ApproachEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 22 2010Emilia Lucia Belsito Abstract An efficient one-pot preparation of N -ethyl- N -4-nitrophenylsulfonyl (nosyl) amino acid methyl esters was accomplished by a simple N -ethylation reaction by using triethyloxonium tetrafluoroborate in the presence of N,N -diisopropylethylamine. The N -ethylated amino acid methyl esters are obtained with total retention of stereochemistry at the original chiral centers. To further broaden the scope of this methodology, the N -ethylated nosyl-protected compounds are easily converted in the more practical fluorenylmethyloxycarbonyl (Fmoc)-protected derivatives. The cleavage of methyl ester by using a mild and neutral method enables the preparation of N -ethyl amino acids that are building blocks suitable for introduction into a peptide chain. The methodology works well with both nosyl- and Fmoc-based solution-phase peptide synthesis. [source] ,-Aminoadamantanecarboxylic Acids Through Direct C,H Bond AmidationsEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 9 2007Lukas Wanka Abstract Utilizing bromine-free, direct C,H bond amidations we have synthesized a large variety of adamantane amides. Depending on the precursors used these amides directly yield pharmaceutically active aminoadamantanes or ,-aminoadamantanecarboxylic acids after hydrolytic cleavage. Theserigid analogues of ,-aminobutyric acid (GABA) were protected at the C- and N-termini and we synthesized a number of peptides incorporating ,-aminoadamantanecarboxylicacids in solution as well as via solid phase peptide synthesis. These peptides are promising scaffolds for applications in medicinal chemistry as well as in organocatalysis.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source] Synthesis, Solution Structure and Biological Activity of Val-Val-Pro-Gln,a Bioactive Elastin PeptideEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 8 2005Caterina Spezzacatena Abstract Val-Val-Pro-Gln (valyl-valyl-prolyl-glutamine) is a small but highly conserved sequence present in all elastins. We describe its synthesis by mixed anhydride solution chemistry as an alternative to solid-phase peptide synthesis (SPPS). The molecular structure of the tetrapeptide in solution was investigated by classical spectroscopy, such as circular dichroism (CD), nuclear magnetic resonance (NMR) and Fourier Transform Infrared Spectroscopy (FTIR). The biological activity of Val-Val-Pro-Gln was evaluated by a bromodeoxyuridine (BrdU) incorporation assay with normal human dermal fibroblasts. This small peptide may play a critical role in control of matrix metabolism through its release from the elastin polypeptide chain during periods of tissue breakdown and remodelling. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005) [source] N -Tetrachlorophthaloyl (TCP) Protection for Solid-Phase Peptide SynthesisEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 17 2004Esther Cros Abstract The N -tetrachlorophthaloyl-(TCP-)amino protecting group has been evaluated for use in solid-phase peptide synthesis. The TCP group was unaffected by exposure to either piperidine or N,N -diisopropylethylamine (DIEA), which suggests compatibility with both Fmoc and Boc solid-phase synthesis protocols. Quantitative TCP removal was achieved by treatment with hydrazine/DMF (3:17) at 35 °C for 30 min or with ethylenediamine/DMF (1:200) at 50 °C for 30 min. Several C-terminal peptide amides were synthesized successfully by following protocols that use hydrazine/DMF (3:17) at 40 °C for 1 h for repetitive deprotection. Treatment of TCP-amines with methylamine or with diamines did not give the corresponding amines (deprotected), but rather the appropriate N,N, -disubstituted tetrachlorophthalamides, which corresponds to a single ring-opening step. This observation was harnessed to prepare linear and macrocyclic peptide,arene hybrids based on the mild reaction of the parent TCP compound with 1,3-diaminopropane/DMF (1:49) at 25 °C for 5 min. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004) [source] Novel N -(2,2-Dimethyl-2H -azirin-3-yl)- L -prolinates as Aib-Pro SynthonsHELVETICA CHIMICA ACTA, Issue 9 2006Simon Stamm Abstract The syntheses of phenacyl N -(2,2-dimethyl-2H -azirin-3-yl)- L -prolinate and allyl N -(2,2-dimethyl-2H -azirin-3-yl)- L -prolinate are reported. Reactions of these 2H -azirin-3-amine derivatives with Z-protected amino acids have shown them to be suitable synthons for the Aib-Pro unit in peptide synthesis. After incorporation into the peptide by means of the ,azirine/oxazolone method', the C-termini of the resulting peptides were deprotected selectively with Zn in AcOH or by a mild Pd0 -promoted procedure, respectively. [source] A p38 MAP kinase regulates the expression of the Aedes aegypti defensin gene in mosquito cellsINSECT MOLECULAR BIOLOGY, Issue 4 2007R. Chen-Chih Wu Abstract An Aedes aegypti p38 (Aap38) mitogen-activated protein kinase was isolated and characterized in this study. The 1761 bp long full-length Aap38 cDNA encodes an open reading frame of 358 amino acids, exhibiting characteristics of Thr/Tyr dual kinase specificities. We showed that bacteria activate both the kinase activity of Aap38 and the expression of the Aedes aegypti defensin A (AaDefA) gene, which is inhibited by a p38 kinase inhibitor SB203580 and dsRNA interference of Aap38. A similar result was obtained by a reporter construct containing the AaDefA regulatory region linked to Ds-Red. The lipopolysaccharide-activated reporter gene was inhibited by SB203580. In addition, Aap38 translocated to the nucleus after lipopolysaccharide induction. Our findings suggest that the p38 protein kinase pathway is involved in the antibacterial peptide synthesis in mosquitoes. [source] Purification and characterization of solvent-tolerant, thermostable, alkaline metalloprotease from alkalophilic Pseudomonas aeruginosa MTCC 7926JOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 9 2009Ulhas Patil Abstract BACKGROUND: Microbial proteases are becoming imperative for commercial applications. The protease secreted by Pseudomonas aeruginosa MTCC 7926, isolated from solvent-contaminated habitat was purified and characterized for activity at various edaphic conditions. The purified alkaline protease was investigated for dehairing of animal skin, anti-staphylococcal activity and processing of X-ray film. RESULTS: The protease was 24-fold purified by ammonium sulfate fractionation, sephadex G-100 gel filtration and DEAE-cellulose, with 36% recovery. KM and Vmax, using casein were 2.94 mg mL,1 and 1.27 µmole min,1, respectively. The apparent molecular mass by SDS-PAGE was 35 kDa. Alkaline protease was active at pH 6,11 and temperature 25,65 °C. Its activity was (a) 86.8% in 100 mmol L,1 NaCl, (b) >95% in metal ions (Mn2+, Ca2+, Mg2+, Fe2+) for 1 h, (c) >90% in bleaching agents and chemical surfactants, (d) 135.4 ± 2.0% and 119.9 ± 6.2% with rhamnolipid and cyclodextrin, respectively, (e) stable in solvents for 5,30 days at 27 °C, and (f) inhibited by EDTA, indicating metalloprotein. CONCLUSION: This work showed that purified protease retained its activity in surfactants, solvents, metals, and bleaching agents. The enzyme is an alternative for detergent formulations, dehairing of animal skin, X-ray film processing, treatment of staphylococcal infections and possibly non-aqueous enzymatic peptide synthesis. Copyright © 2009 Society of Chemical Industry [source] Synthesis of tritium labelled delta sleep-inducing peptideJOURNAL OF LABELLED COMPOUNDS AND RADIOPHARMACEUTICALS, Issue 7 2001Matthieu Giraud Abstract The ,,, -dehydro precursor of the delta sleep-inducing peptide (DSIP) for tritiation was prepared prior to tritiation using a 3+6 fragment coupling strategy on a solid support. The first fragment, ,,, -dehydrotripeptide, was prepared in solution in five steps in 79% overall yield while the second fragment was obtained by a step by step peptide synthesis on a Wang resin using an Fmoc strategy. The ,,, -dehydrotripeptide was coupled to the fragment linked to the resin, followed by a deprotection/cleavage step to yield the ,,, -dehydro-DSIP, 7. Catalytic reduction of unsaturated DSIP using tritium gas and palladium oxide as catalyst gave [3H]DSIP having a specific activity of 1.184 TBq/mmol(32 Ci/mmol). Copyright © 2001 John Wiley & Sons, Ltd. [source] Oligohis-tags: mechanisms of binding to Ni2+ -NTA surfacesJOURNAL OF MOLECULAR RECOGNITION, Issue 4 2009Steven Knecht Abstract Since immobilized metal ion affinity chromatography (IMAC) was first reported, several modifications have been developed. Among them, Ni2+ immobilized by chelation with nitrilotriacetic acid (NTA) bound to a solid support has become the most common method for the purification of proteins carrying either a C - or N -terminal histidine (His) tag. Despite its broad application in protein purification, only little is known about the binding properties of the His-tag, and therefore almost no thermodynamic and kinetic data are available. In this study, we investigated the binding mechanism of His-tags to Ni2+ -NTA. Different series of oligohistidines and mixed oligohistidines/oligoalanines were synthesized using automated solid-phase peptide synthesis (SPPS). Binding to Ni2+ -NTA was analyzed both qualitatively and quantitatively with surface plasmon resonance (SPR) using commercially available NTA sensor chips from Biacore. The hexahistidine tag shows an apparent equilibrium dissociation constant (KD) of 14,±,1,nM and thus the highest affinity of the peptides synthesized in this study. Furthermore, we could demonstrate that two His separated by either one or four residues are the preferred binding motifs within hexahis tag. Finally, elongation of these referred motifs decreased affinity, probably due to increased entropy costs upon binding. Copyright © 2009 John Wiley & Sons, Ltd. [source] Modular, self-assembling peptide linkers for stable and regenerable carbon nanotube biosensor interfaces,JOURNAL OF MOLECULAR RECOGNITION, Issue 4 2006Mark R. Contarino Abstract As part of an effort to develop nanoelectronic sensors for biological targets, we tested the potential to incorporate coiled coils as metallized, self-assembling, site-specific molecular linkers on carbon nanotubes (CNTs). Based on a previously conceived modular anchor-probe approach, a system was designed in which hydrophobic residues (valines and leucines) form the interface between the two helical peptide components. Charged residues (glutamates and arginines) on the borders of the hydrophobic interface increase peptide solubility, and provide stability and specificity for anchor-probe assembly. Two histidine residues oriented on the exposed hydrophilic exterior of each peptide were included as chelating sites for metal ions such as cobalt. Cysteines were incorporated at the peptide termini for oriented, thiol-mediated coupling to surface plasmon resonance (SPR) biosensor surfaces, gold nanoparticles or CNT substrates. The two peptides were produced by solid phase peptide synthesis using Fmoc chemistry: an acidic 42-residue peptide E42C, and its counterpart in the heterodimer, a basic 39-residue peptide R39C. The ability of E42C and R39C to bind cobalt was demonstrated by immobilized metal affinity chromatography and isothermal titration calorimetry. SPR biosensor kinetic analysis of dimer assembly revealed apparent sub-nanomolar affinities in buffers with and without 1,mM CoCl2 using two different reference surfaces. For device-oriented CNT immobilization, R39C was covalently anchored to CNT tips via a C-terminal cysteine residue. Scanning electron microscopy was used to visualize the assembly of probe peptide (E42C) N-terminally labeled with 15,nm gold nanoparticles, when added to the R39C-CNT surface. The results obtained open the way to develop CNT tip-directed recognition surfaces, using recombinant and chemically synthesized chimeras containing binding epitopes fused to the E42C sequence domain. Copyright © 2006 John Wiley & Sons, Ltd. [source] Synthesis of pathological and nonpathological human exon 1 huntingtinJOURNAL OF PEPTIDE SCIENCE, Issue 7 2010David Singer Abstract Huntington's disease (HD) is a neurodegenerative disorder that affects approximately 1 in 10 000 individuals. The underlying gene mutation was identified as a CAG-triplet repeat expansion in the gene huntingtin. The CAG sequence codes for glutamine, and in HD, an expansion of the polyglutamine (poly-Q) stretch above 35 glutamine residues results in pathogenicity. It has been demonstrated in various animal models that only the expression of exon 1 huntingtin, a 67-amino acid-long polypeptide plus a variable poly-Q stretch, is sufficient to cause full HD-like pathology. Therefore, a deeper understanding of exon 1 huntingtin, its structure, aggregation mechanism and interaction with other proteins is crucial for a better understanding of the disease. Here, we describe the synthesis of a 109-amino acid-long exon 1 huntingtin peptide including a poly-Q stretch of 42 glutamines. This microwave-assisted solid phase peptide synthesis resulted in milligram amounts of peptide with high purity. We also synthesized a nonpathogenic version of exon 1 huntingtin (90-amino acid long including a poly-Q stretch of 23 glutamine residues) using the same strategy. In circular dichroism spectroscopy, both polypeptides showed weak alpha-helical properties with the longer peptide showing a higher helical degree. These model peptides have great potential for further biomedical analyses, e.g. for large-scale pre-screenings for aggregation inhibitors, further structural analyses as well as protein,protein interaction studies. Copyright © 2010 European Peptide Society and John Wiley & Sons, Ltd. [source] Microwave-assisted TFA cleavage of peptides from Merrifield resinJOURNAL OF PEPTIDE SCIENCE, Issue 1 2010Alicja Kluczyk Abstract Microwave-assisted (MW) reactions are of special interest to the chemical community due to faster reaction times, cleaner reactions and higher product yields. The adaptation of MW to solid phase peptide synthesis resulted in spectacular syntheses of difficult peptides. In the case of Merrifield support, used frequently in synthesis of special peptides, the conditions used in product cleavage are not compatible with off-resin monitoring of the reaction progress. The application of MW irradiation in product removal from Merrifield resin using trifluoroacetic acid (TFA) was investigated using model tetrapeptides and the effects were compared with standard trifluoromethanesulphonic acid (TFMSA) cleavage using elemental analysis as well as chromatographic (HPLC) and spectroscopic (IR) methods. The deprotection of benzyloxycarbonyl and benzyl groups in synthetic bioactive peptides was analyzed using LC-MS and MS/MS experiments. In a 5 min microwave-assisted TFA reaction at low temperature, the majority of product is released from the resin, making the analytical scale MW-assisted procedure a method of choice in monitoring the reactions carried out on Merrifield resin due to the short reaction time and compatibility with HPLC and ESI-MS conditions. Copyright © 2009 European Peptide Society and John Wiley & Sons, Ltd. [source] Microwave-assisted solid-phase peptide synthesis at 60 °C: alternative conditions with low enantiomerization,JOURNAL OF PEPTIDE SCIENCE, Issue 12 2009Carina Loffredo Abstract Several conditions have been used in the coupling reaction of stepwise SPPS at elevated temperature (SPPS-ET), but we have elected the following as our first choice: 2.5-fold molar excess of 0.04,0.08 M Boc or Fmoc-amino acid derivative, equimolar amount of DIC/HOBt (1:1) or TBTU/DIPEA (1:3), 25% DMSO/toluene, 60 °C, conventional heating. In this study, aimed to further examine enantiomerization under such condition and study the applicability of our protocols to microwave-SPPS, peptides containing L -Ser, L -His, L -Cys and/or L -Met were manually synthesized traditionally, at 60 °C using conventional heating and at 60 °C using microwave heating. Detailed assessment of all crude peptides (in their intact and/or fully hydrolyzed forms) revealed that, except for the microwave-assisted coupling of L -Cys, all other reactions occurred with low levels of amino acid enantiomerization (<2%). Therefore, herein we (i) provide new evidences that our protocols for SPPS at 60 °C using conventional heating are suitable for routine use, (ii) demonstrate their appropriateness for microwave-assisted SPPS by Boc and Fmoc chemistries, (iii) disclose advantages and limitations of the three synthetic approaches employed. Thus, this study complements our past research on SPPS-ET and suggests alternative conditions for microwave-assisted SPPS. Copyright © 2009 European Peptide Society and John Wiley & Sons, Ltd. [source] Quality specifications for peptide drugs: a regulatory-pharmaceutical approachJOURNAL OF PEPTIDE SCIENCE, Issue 11 2009Valentijn Vergote Abstract Peptide drugs, as all types of pharmaceuticals, require adequate specifications (i.e. quality attributes, procedures and acceptance criteria) as part of their quality assurance to ensure the safety and efficacy of drug substances (i.e. active pharmaceutical ingredients) and drug products (i.e. finished pharmaceutical dosage forms). Compendial monographs are updated regularly to keep up with the most recent advances in peptide synthesis (e.g. reduced by-products) and analytical technology. Nevertheless, currently applied pharmacopoeial peptide specifications are barely harmonized yet (e.g. large differences between the European Pharmacopoeia and the United States Pharmacopeia), increasing the manufacturers' burden of performing analytical procedures in different ways, using different acceptance criteria. Additionally, the peptide monographs are not always consistent within a single pharmacopoeia. In this review, we highlight the main differences and similarities in compendial peptide specifications (including identification, purity and assay). Based on comparison, and together with additional information from peptide drug substance manufacturers and public evaluation reports on registration files of non-pharmacopoeial peptide drugs, a consistent monograph structure is proposed. Copyright © 2009 European Peptide Society and John Wiley & Sons, Ltd. [source] Solid-phase peptide synthesis using acetonitrile as a solvent in combination with PEG-based resinsJOURNAL OF PEPTIDE SCIENCE, Issue 10 2009Gerardo A. Acosta Abstract This manuscript shows that ACN can be an excellent choice for the coupling of hindered amino acids as illustrated by the coupling of Fmoc-amino acids on free amino acids anchored on a BAL synthesis. Furthermore, ACN can be a good alternative for solid-phase peptide synthesis in the absence of DMF (washings, removal of Fmoc, and coupling). Copyright © 2009 European Peptide Society and John Wiley & Sons, Ltd. [source] Synthesis and application of N -[1-(4-(4-fluorophenyl)-2,6-dioxocyclohexylidene)ethyl] (Fde)-protected amino acids for optimization of solid-phase peptide synthesis using gel-phase 19F NMR spectroscopyJOURNAL OF PEPTIDE SCIENCE, Issue 4 2009Maciej Pudelko Abstract N -[1-(4-(4-fluorophenyl)-2,6-dioxocyclohexylidene)ethyl] (Fde) protected amino acids have been prepared and applied in solid-phase peptide synthesis monitored by gel-phase 19F NMR spectroscopy. The Fde protective group could be cleaved with 2% hydrazine or 5% hydroxylamine solution in DMF as determined with gel-phase 19F NMR spectroscopy. The dipeptide Ac- L -Val- L -Val-NH2 12 was constructed using Fde- L -Val-OH and no noticeable racemization took place during the amino acid coupling with N,N,-diisopropylcarbodiimide and 1-hydroxy-7-azabenzotriazole or Fde deblocking. To extend the scope of Fde protection, the hydrophobic nonapeptide LLLLTVLTV from the signal sequence of mucin MUC1 was successfully prepared using Fde- L -Leu-OH at diagnostic positions. Copyright © 2009 European Peptide Society and John Wiley & Sons, Ltd. [source] Investigation of the synthetic route to pepstatin analogues by SPPS using O -protected and O -unprotected statine as building blocksJOURNAL OF PEPTIDE SCIENCE, Issue 4 2009Cosimo D. Cadicamo Abstract The synthetic route to pepstatin derivatives by a solid phase peptide synthesis using either O -protected or O -unprotected statine as a building block has been investigated. Statine was prepared according to a modified literature procedure, whereas protection of its 3-hydroxyl moiety using tert -butyldimethylsilylchloride (TBSCl) provided the novel O -TBS-protected statine building block. The O - tert -butyldimethylsilyl (TBS)-protected statine approach provides an improved synthetic strategy for the preparation of statine-containing peptides as demonstrated by the synthesis of the pepstatin analogue iva-Val- Leu -Sta-Ala-Sta. Copyright © 2009 European Peptide Society and John Wiley & Sons, Ltd. [source] Microwave-assisted Boc-solid phase peptide synthesis of cyclic cysteine-rich peptidesJOURNAL OF PEPTIDE SCIENCE, Issue 6 2008Abstract In this study we describe the first protocols for the synthesis of cystine-rich peptides in the presence of microwave radiation with Boc-solid phase peptide synthesis (SPPS). This method is exemplified for macrocyclic peptides known as cyclotides, which comprise ,30 amino acids and incorporate a cystine knot arrangement of their three disulfide bonds. However, the method is broadly applicable for a wide range of peptides using Boc-SPPS, especially for SPPS of large peptides via native chemical ligation. Microwave radiation produces peptides in high yield and with high purity, and we were able to reduce the time for the assembly of ,30 mer peptide chains to an overnight reaction in the automated microwave-assisted synthesis. Copyright © 2007 European Peptide Society and John Wiley & Sons, Ltd. [source] Fmoc-based solid phase chemical synthesis of 71-meric neuregulin 1-,1, an epidermal growth factor-like domainJOURNAL OF PEPTIDE SCIENCE, Issue 3 2008Taeko Kakizawa Abstract The human neuregulin 1-,1 (NRG1-,1, amino acid residues 176,246) was chemically synthesized by Fmoc-based solid phase peptide synthesis (SPPS) followed by folding in a redox buffer. The biological activity of the synthesized NRG1-,1 was confirmed by ligand-induced tyrosine phosphorylation on Chinese hamster ovary (CHO) cells expressing ErbB-4. Copyright © 2007 European Peptide Society and John Wiley & Sons, Ltd. [source] | |||||||||||||||||||||||||||||||