摘要:

AbstractApplications of cysteine‐insertion and thioether linkage approaches to the preparation of a number of bioactive peptide conjugates are reported. Peptides containing epitopes from (i) herpes simplex virus type 1 glycoprotein D, (ii) a specificN‐terminal β‐amyloid epitope recognized by therapeutically active antibodies, and (iii) a GnRH‐III peptide from sea lamprey with antitumour activity, were elongated with Cys residues and attached to a chloroacetylated tetratuftsin derivative carrier via a thioether linkage either directly, or by insertion of a spacer. The structures and molecular homogeneity of all the peptide conjugates were ascertained by HPLC, MALDI and electrospray mass spectrometry. The use of a spacer such as an oligoglycine or GFLG‐tetrapeptide gave an increased yield in the conjugation reaction and enhanced reaction rates. In the formation of cysteinyl‐thioether linkages, it was found that the position of flanking Cys residues markedly influenced the conjugation reaction and the formation of intermolecular epitope disulfide‐dimers.C‐terminal Cys residues gave thioether conjugates with significantly diminished epitope‐dimerization, while Cys at theN‐terminal caused rapid disulfide‐dimerization, thereby preventing efficient conjugation. Copyright © 2004 European Peptide Society a

ISSN:1075-2617    

DOI:10.1002/psc.583

出版商:John Wiley&Sons, Ltd.    

年代:2004

数据来源: WILEY

摘要:

AbstractDefensins are phylogenetically ancient antibacterial polypeptides found in plants and animals. Isolation of the cDNA and genomic sequences encoding the scorpion (Leiurus quinquestriatus hebraeus) defensin revealed similarity to scorpion neurotoxins in gene organization (two exons and a phase I intron) and intron characteristics (conserved acceptor, donor and putative branch sites). This commonality, alongside a similar core structure, protein sequence and bioactivity suggest that arthropod defensins and scorpion neurotoxins share a common ancestor. Interestingly, phylogenetic analysis of defensins and scorpion neurotoxins illuminates for the first time a putative evolutionary trajectory for scorpion sodium and potassium channel neurotoxins. Copyright © 2004 European Peptide Society and John Wiley&Sons, Ltd

ISSN:1075-2617    

DOI:10.1002/psc.578

出版商:John Wiley&Sons, Ltd.    

年代:2004

数据来源: WILEY

摘要:

AbstractMonoliths based on a copolymer of glycidyl methacrylate (GMA) and ethylene dimethacrylate (EDMA) can be used directly as sorbents for affinity chromatography after solid phase peptide synthesis. The quality of the synthesized products, the amount of grown peptides on a support and the reproducibility of the process must be considered. A determination of the quantity of the introducing β‐Ala (and, consequently, the total amount of synthesized peptide) was carried out. Three peptides complementary to recombinant tissue plasminogen activator (t‐PA) have been synthesized using Fmoc‐chemistry on GMA‐EDMA disks. The peptidyl ligands were analysed by amino acid analysis, ES‐MS and HPLC methods.The affinity binding parameters were obtained from frontal elution data. The results were compared with those established for GMA‐EDMA affinity sorbents formed by the immobilization of the same but separately synthesized and purified ligands. The immobilization on GMA‐EDMA disks was realized using a one‐step reaction between the amino groups of the synthetic ligand and the original epoxy groups of monolithic material. The affinity constants found for two kinds of sorbent did not vary significantly. Finally, the directly obtained affinity sorbents were tested for t‐PA separation from a cellular supernatant. Copyright © 2004 European Peptide Society and J

ISSN:1075-2617    

DOI:10.1002/psc.584

出版商:John Wiley&Sons, Ltd.    

年代:2004

数据来源: WILEY

摘要:

AbstractMechanisms of the reactions of representative dipeptides (Gly2, Gly‐Ala), oligopeptides (Gly3, Gly4) and the polypeptide (poly‐Gly)n) in solution and clay suspensions at 85 °C were investigated. The reaction products and their yields were analysed and determined by means of HPLC. Interestingly, hydrolysis, where water molecules act as the reactant, was not the main reaction, even for oligopeptides. Formation of cyclic dipeptides prevailed in the reactions of dimers as well as oligopeptides. The breakdown of oligopeptide molecules proceeded via an intramolecular cyclization reaction. For example, the reaction of Gly3led to the formation of equal amounts of cyclic dipeptide, c(Gly)2and Gly. The presence of clay (montmorillonite) significantly increased yields in the reactions of dipeptides but it did not have much effect on the reactions of oligopeptides. However, an opposite effect of clay, protection of poly(Gly)nagainst decomposition, was proven. Copyright © 2004 European Peptide Society and John Wiley&Sons

ISSN:1075-2617    

DOI:10.1002/psc.580

出版商:John Wiley&Sons, Ltd.    

年代:2004

数据来源: WILEY