Synthesis and conformation of dipeptide taste ligands containinghomo-β-amino acid residues
摘要:
The synthesis and conformational properties of a series of dipeptide taste ligands, differing from the commercial sweetener aspartame by the presence of a methylene group between the C-alpha and the C' carbon atoms (as in homo-beta-residues) in either the L-Asp or the L-Phe residues, are described. Homo-beta-residues such as homo-beta-aspartic acid, homo-beta-phenylglycine and homo-beta-phenylalanine, obtained by homologation of the corresponding proteinogenic alpha-amino acids, have been used in the solution peptide synthesis of the following aspartame analogues in protected and unprotected forms: NH2-homo-beta-(L or D)-Asp-L-Phe-OMe, NH2-L-Asp-homo-beta-L-Phg-OMe and NH2-L-Asp-homo-beta-L-Phe-OMe. Lengthening of the peptide skeleton at the L-Asp site results in a drastic loss of sweetness with the production of tasteless compounds; on the other hand, lengthening of the skeleton at the C-terminal L-Phe site partially mantains the sweet taste in both NH2-L-Asp-homo-beta-L-Phe-OMe and NH2-L-Asp-homo-beta-L-Phg-OMe. The solution conformation of the synthesized dipeptide taste ligands was investigated by NMR and circular dichroism techniques. The analysis of NMR data combined with restrained molecular dynamics calculations shows that all peptides are fairly flexible and they do not assume a preferred conformation in DMSO and methanol. The peptides containing homo-beta-L-Phe and homo-beta-L-Phg do adopt a discrete number of conformations among which mainly extended and 'L-shaped' conformation are represented. The circular dichroism spectra are consistent with the NMR results, indicating a significant flexibility for these compounds. Copyright (C) 1999 John Wiley & Sons, Ltd.
Synthesis and conformation of dipeptide taste ligands containinghomo-β-amino acid residues
摘要:
The synthesis and conformational properties of a series of dipeptide taste ligands, differing from the commercial sweetener aspartame by the presence of a methylene group between the C-alpha and the C' carbon atoms (as in homo-beta-residues) in either the L-Asp or the L-Phe residues, are described. Homo-beta-residues such as homo-beta-aspartic acid, homo-beta-phenylglycine and homo-beta-phenylalanine, obtained by homologation of the corresponding proteinogenic alpha-amino acids, have been used in the solution peptide synthesis of the following aspartame analogues in protected and unprotected forms: NH2-homo-beta-(L or D)-Asp-L-Phe-OMe, NH2-L-Asp-homo-beta-L-Phg-OMe and NH2-L-Asp-homo-beta-L-Phe-OMe. Lengthening of the peptide skeleton at the L-Asp site results in a drastic loss of sweetness with the production of tasteless compounds; on the other hand, lengthening of the skeleton at the C-terminal L-Phe site partially mantains the sweet taste in both NH2-L-Asp-homo-beta-L-Phe-OMe and NH2-L-Asp-homo-beta-L-Phg-OMe. The solution conformation of the synthesized dipeptide taste ligands was investigated by NMR and circular dichroism techniques. The analysis of NMR data combined with restrained molecular dynamics calculations shows that all peptides are fairly flexible and they do not assume a preferred conformation in DMSO and methanol. The peptides containing homo-beta-L-Phe and homo-beta-L-Phg do adopt a discrete number of conformations among which mainly extended and 'L-shaped' conformation are represented. The circular dichroism spectra are consistent with the NMR results, indicating a significant flexibility for these compounds. Copyright (C) 1999 John Wiley & Sons, Ltd.
Cytotoxic dimers comprising CBI-based and/or CPI-based sub-units, antibody drug conjugates comprising such dimers, and to methods for using the same to treat cancer and other conditions.
Cytotoxic dimers comprising CBI-based and/or CPI-based sub-units, antibody drug conjugates comprising such dimers, and to methods for using the same to treat cancer and other conditions.
library of bifunctional cyclic peptides as FK506 and rapamycin analogues, which were referred to as “rapalogs”. Each rapalog consists of a common FKBP-binding moiety and a variable effector domain. The rapalogs were tested for binding to FKBP12 by a fluorescence polarization competition assay. Our results show that FKBP12 binds to most of the rapalogs with high affinity (KI values in the nanomolar to
Method for preparing a ligand presenting assembly (LPA), an LPA and uses thereof
申请人:Statens Serum Institut
公开号:US20040086949A1
公开(公告)日:2004-05-06
The present invention relates to a method for preparing a ligand presenting assembly (LPA), an LPA, an immunological composition and a vaccine. The invention further relates to a method for generating antibodies, a kit for use in diagnosis and use of an LPA for preparing a pharmaceutical composition.
Radiolabeled cyclic arginine-glycine-aspartic (RGD) peptides can be used for noninvasive determination of integrin αvβ3 expression in tumors. In this study, we performed radiosynthesis and biological evaluation of a new 18F-labeled RGD homodimeric peptide with one 8-amino-3,6-dioxaoctanoic acid (PEG2) linker on the glutamate β-amino group (18F-FP-PEG2-β-Glu-RGD2) as a symmetric PET tracer for tumor imaging. Biodistribution studies showed that radioactivity of 18F-FP-PEG2-β-Glu-RGD2 was rapidly cleared from blood by predominately renal excretion. MicroPET-CT imaging with 18F-FP-PEG2-β-Glu-RGD2 revealed high tumor contrast and low background in A549 human lung adenocarcinoma-bearing mouse models, PC-3 prostate cancer-bearing mouse models, and orthotopic transplanted C6 brain glioma models. 18F-FP-PEG2-β-Glu-RGD2 exhibited good stability in vitro and in vivo. The results suggest that this tracer is a potential PET tracer for tumor imaging.