摘要:

AbstractFluorescent cell analytical techniques require the incorporation of a fluorophore into the target molecule without causing a significant change in the native conformation. Many short peptides have a limited number of reactive groups that can be labeled without affecting the biological activity. In this work we present several methods for labeling β‐amyloid peptides (βA[25–35], βA[1–40]) and their derivatives (LPFFD, RIIGL and RVVIA) with different chromophores exclusively at theN‐terminus. In the case of liquid‐phase labeling, fluorescein isothiocyanate was used. The side‐chain amino function of Lys, if present in the sequence, was protected with an Fmoc group, whereby the hydrophobic character of the peptide was further increased. The labeling reaction was carried out in an appropriate deaggregating solvent, DMSO. For solid‐phase labeling, 5(6)‐carboxyfluorescein and 7‐amino‐4‐methyl‐3‐coumarinylacetic acid were applied. Several cleavage cocktails were tested for removal of the labeled amyloid peptides from the resin in order to completely suppress the oxidation of Met. Copyright © 2001 European Peptide Soc

ISSN:1075-2617    

DOI:10.1002/psc.346

出版商:John Wiley&Sons, Ltd.    

年代:2001

数据来源: WILEY

摘要:

AbstractThe synthesis of novel Boc/acyl protected monomers for the synthesis of peptide nucleic acid (PNA) is described. The oligomerization protocol using these new monomers has been optimized with regard to coupling reagents. The use of base‐labile acyl protecting groups at the exocyclic amines of the heterocyclic bases (isobutyryl for guanine and benzoyl for adenine and cytosine) and a PAM‐linked solid support offers an attractive alternative to the present procedures used in PNA synthesis. This strategy has been applied for the synthesis of a test 17mer PNA on both control pore glass (CPG) and a polystyrene MBHA support and was used in the preparation of PNA–DNA chimeras. Copyright © 2001 European Peptide Society and John Wiley&Son

ISSN:1075-2617    

DOI:10.1002/psc.333

出版商:John Wiley&Sons, Ltd.    

年代:2001

数据来源: WILEY

摘要:

AbstractFor the purpose of evaluating substitution effects in theortho,metaorparapositions of the aromatic ring of tyrosine or phenylalanine in position 2 of oxytocin on uterotonic activityin vitroin the presence and absence of magnesium ions, six new analogues of oxytocin ([

ISSN:1075-2617    

DOI:10.1002/psc.334

出版商:John Wiley&Sons, Ltd.    

年代:2001

数据来源: WILEY

摘要:

AbstractA model peptide, FKCRRWQWRMKKLGA, residues 17–31 of bovine lactoferricin, has been subjected to structure–antibacterial activity relationship studies. The two Trp residues are very important for antibacterial activity, and analogue studies have demonstrated the significance of the size, shape and aromatic character of the side chains. In the current study we have replaced Trp residues in the model peptide with bulky aromatic amino acids to elucidate further the importance of size and shape. The counterproductive Cys residue in position 3 was also replaced by these aromatic amino acids. The largest aromatic amino acids employed resulted in the most active peptides. The peptides containing these hydrophobic residues were generally more active againstStaphylococcus aureusthan againstEscherichia coli, indicating that the bacterial specificity as well as the antibacterial efficiency can be altered by employing large hydrophobic aromatic amino acid residues. Copyright © 2001 European Peptide Society and John Wiley&Sons,

ISSN:1075-2617    

DOI:10.1002/psc.338

出版商:John Wiley&Sons, Ltd.    

年代:2001

数据来源: WILEY

摘要:

AbstractFrom the culture broths of the moldStilbella flavipesCBS 146.81, a mixture of polypeptides could be isolated by adsorption on XAD polystyrene resin and purified by Sephadex LH‐20 chromatography. Using preparative thin‐layer chromatography (TLC) three groups of peptides, named stilboflavins (SF) A, B, and C could be separated. Each of the groups showed microheterogeneity when investigated by high‐performance liquid chromatography (HPLC). Employing on‐line HPLC‐electrospray ionization tandem mass spectrometry in the positive and negative ionization mode, together with gas chromatography‐selected ion monitoring mass spectrometry, enantioselective GC and quantitative amino acid analysis, the sequences of stilboflavins A and B could be determined. Exchange of Glu in stilboflavins A peptides (acidic) against Gln in stilboflavins B peptides (neutral) is the rational for different polarity of the peptide groups and their separatability by TLC. Since SF A and B are bioactiveN‐acetylated 20‐residue peptides with a high proportion of α‐aminoisobutyric acid andC‐terminal bonded amino alcohols (either leucinol, isoleucinol or valinol) the peptides belong to the group of peptaibol antibiotics. Copyright © 2001 European Peptide Society and

ISSN:1075-2617    

DOI:10.1002/psc.335

出版商:John Wiley&Sons, Ltd.    

年代:2001

数据来源: WILEY