Search results for "SOLID-PHASE"
showing 10 items of 178 documents
Synthesis of Biologically Interesting Glycopeptides.
1992
哺乳動物に見い出される大部分のタンパクは糖タンパクである。それらの糖鎖は生物学的選択性、特に膜上での認識過程に重要な働きをしている。全ての糖タンパクは糖鎖とペプチドとの間にグリコシド結合を有している。それゆえに糖ペプチドの化学合成は、立体特異的なグリコシド結合の生成と、グリコシド結合に影響を与えない選択的な保護が要求される。ベンジルグループとそれらの水素添加による脱離法は、これらの要求を満たす。しかしながら、これらの保護法を用いる方法は糖質の水酸基のブロックを必要とするので、ペプチド部分の官能基は撰択的に脱離可能でそしてベンジル基に対して orthogonal に安定なグループで保護されなければならない。この意味においてフルオレニルメトキシカルボニル (Fmoc) 基と、弱塩基、モルフォリンによる脱離と、パラジウム (0) 触媒によるアリル基転移によって脱離可能なアリルオキシカルボニル (Aloc) 基は、糖ペプチド化学においてアミノ基の保護基として有用である事が明らかにされた。同様なパラジウム (0) の化学を用いるアリルエステルと、酸により除去可能なtert-ブチルエステルはカルボキシル基の保護に有用である事が分かった。ベンジル基とアリルエステル (HYCRAM™) を用いる糖ペプチドの固相合成におけるアンカーシステムとして有効に利用される事が示された。
Polymer-based materials modified with magnetite nanoparticles for enrichment of phospholipids
2018
[EN] A polymeric material modified with magnetic nanoparticles (MNPs) has been synthesized and evaluated as sorbent both for solid-phase extraction (SPE) and dispersive magnetic solid-phase extraction (MSPE) of phospholipids (PLs) in human milk samples. The synthesized sorbent was characterized by scanning electron microscopy and its iron content was also determined. Several experimental variables that affect the extraction performance (e.g. loading solvent, breakthrough volume and loading capacity) were investigated and a comparison between conventional SPE and MSPE modalities was done. The proposed method was satisfactorily applied to the analysis of PLs in human milk fat extracts in diff…
FINDUS: An Open-Source 3D Printable Liquid-Handling Workstation for Laboratory Automation in Life Sciences
2020
3D-printed laboratory devices can enable ambitious research purposes even at a low-budget level. To follow this trend, here we describe the construction, calibration, and usage of the FINDUS (Fully Integrable Noncommercial Dispensing Utility System). We report the successful 3D printing and assembly of a liquid-handling workstation for less than $400. Using this setup, we achieve reliable and flexible liquid-dispensing automation with relative pipetting errors of less than 0.3%. We show our system is well suited for several showcase applications from both the biology and chemistry fields. In support of the open-source spirit, we make all 3D models, assembly instructions, and source code ava…
Towards a fully synthetic MUC1-based anticancer vaccine: efficient conjugation of glycopeptides with mono-, di-, and tetravalent lipopeptides using c…
2011
Abstract The membrane-bound tumor-associated glycoprotein MUC1 is aberrantly glycosylated in cancer cells compared with normal cells, and is therefore considered an attractive target for cancer immunotherapy. However, tumor-associated glycopeptides from MUC1 do not elicit a sufficiently robust immune response. Therefore, antitumor vaccines were developed, which consist of MUC1 glycopeptides as the B epitopes and immune-stimulating toll-like receptor 2 (TLR 2) lipopeptide ligands. These fully synthetic vaccine candidates were prepared by solid-phase synthesis of the MUC1 glycopeptides. The Pam(3) Cys lipopeptide, also synthesized on solid-phase, was C-terminally coupled to oligovalent lysine…
Total Synthesis of the Glycopeptide Recognition Domain of the P-Selectin Glycoprotein Ligand 1
2008
The (2-phenyl-2-trimethylsilyl)ethyl-(PTMSEL)-linker in the synthesis of glycopeptide partial structures of complex cell surface glycoproteins.
2003
The (2-phenyl-2-trimethylsilyl)ethyl-(PTMSEL) linker represents a novel fluoride-sensitive anchor for the solid-phase synthesis of protected peptides and glycopeptides. Its cleavage is achieved under almost neutral conditions using tetrabutylammonium fluoride trihydrate in dichloromethane thus allowing the construction of complex molecules sensitive to basic and acidic media commonly required for the cleavage of standard linker systems. The advantages of the PTMSEL linker are demonstrated in the synthesis of glycopeptides from the liver intestine (LI)-cadherin and the mucin MUC1, bearing carbohydrate moieties such as N-linked chitobiose or O-linked sialyl-T(N)-residues. The synthesis of the…
ChemInform Abstract: Solution versus Fluorous versus Solid-Phase Synthesis of 2,5-Disubstituted 1,3-Azoles. Preliminary Antibacterial Activity Studie…
2010
A small library of compounds with an oxa(thia)zole scaffold and structural diversity in both positions 2 and 5 has been synthesized. Double acylation of a protected glycine affords intermediate alpha-amido-beta-ketoesters, which in turn can be dehydrated to afford 1,3-oxazoles or reacted with Lawesson's reagent to furnish 1,3-thiazoles. This procedure was designed with its adaptation to fluorous techniques in mind. Thus, when a protected glycine with a fluorous tag in the ester moiety is used as a starting material, the synthesis can be easily completed without column chromatography purification of intermediate compounds with good to excellent yields, thus affording a suitable entry to the …
Emerging hierarchical porous silica-based nanomaterials as sorbents for the analytical determination of organic hazardous compounds
2022
Actualment, l'exposició humana a compostos orgànics perillosos s'ha convertit en una preocupació molt important. La presència de contaminants orgànics al medi ambient ha provocat l'aparició de noves normatives per tal de restringir o prohibir aquestes substàncies perilloses, i el desenvolupament de noves metodologies analítiques per a la seua determinació ha esdevingut un gran repte per a la química analítica actual. A més a més, a part del desenvolupament de noves tècniques instrumentals, l'anàlisi de matrius complexes requereix d’un pas de preconcentració i neteja, per al qual s’han proposat diversos materials nous com a alternatives als adsorbents clàssics. Entre ells, la sílice mesoporo…
Synthetic vaccines consisting of tumor-associated MUC1 glycopeptide antigens and a T-cell epitope for the induction of a highly specific humoral immu…
2008
Sensory and chemical drivers of wine minerality aroma: An application to Chablis wines
2017
The goal of this work was to evaluate the effect of vineyard position on the minerality of wines and to establish relationships between minerality scores, sensory descriptors and chemical composition. Sensory analyses included minerality rating and free description performed by wine professionals under two conditions: orthonasal olfaction alone and global tasting. Chemical characterization included analysis of major and minor volatile compounds, volatile sulphur compounds, mercaptans, metals, anions and cations. Results showed a significant effect of the river bank on wine minerality scores only in the orthonasal olfaction condition, samples from the left being more mineral than those from …