Search results for "glycopeptide"

C-Glycosyl amino acids through hydroboration-cross-coupling of exo-glycals and their application in automated solid-phase synthesis.

2013

O-Glycosylation is one of the most important post-translational modifications of proteins. The attachment of carbohydrates to the peptide backbone influences the conformation as well as the solubility of the conjugates and can even be essential for binding to specific ligands in cell-cell interactions or for active transport over membranes. This makes glycopeptides an interesting class of compounds for medical applications. To enhance the long-term availability of these molecules in vivo, the stabilization of the glycosidic bond between the amino acid residue and the carbohydrate is of interest. The described modular approach affords β-linked C-glycosyl amino acids by a sequence of Petasis …

Synthetic Antitumor Vaccines Through Coupling of Mucin Glycopeptide Antigens to Proteins

2017

The requirements for coupling reactions of carbohydrate molecules very much depend upon the biological recognition processes that should be investigated and upon the target structures of the desired carbohydrate ligand. If the carbohydrate conjugate itself is the recognized ligand, as for example, the binding site of a P-selectin ligand comprising sialyl-LewisX and a specific peptide sequence, the natural glycoside bond must be installed. A stereoselective and regioselective block glycosylation between a sialyl-LewisX trichloroacetimidate and a partially deprotected Thomsen–Friedenreich antigen derivative was developed to achieve this aim. In contrast, the coupling reactions by which glycop…

Enzymatic glycosylation of o-glycopeptides

1992

Abstract O-Glycosylation of serine derivatives carried out with N-urethane protected glucosamine yields O-glycopeptides which are regio- and stereoselectively galactosylated with the aid of β-1,4-galactosyltransferase (EC 2.4.1.22).

Synthesis of glycosylated β3-homo-threonine conjugates for mucin-like glycopeptide antigen analogues

2010

Glycopeptides from the mucin family decorated with tumour-associated carbohydrate antigens (TACA) have proven to be important target structures for the development of molecularly defined anti-cancer vaccines. The strategic incorporation of β-amino acid building blocks into such mucin-type sequences offers the potential to create pseudo-glycopeptide antigens with improved bioavailability for tumour immunotherapy. Towards this end, TN and TF antigen conjugates O-glycosidically linked to Fmoc-β3-homo-threonine were prepared in good yield via Arndt–Eistert homologation of the corresponding glycosyl α-amino acid derivative. By incorporation of TN-Fmoc-β3hThr conjugate into the 20 amino acid tand…

[1] Neoglycoproteins from synthetic glycopeptides

1994

Publisher Summary Saccharide side chains of glycoproteins influence the physicochemical properties of the biomacromolecules and their stability against proteolytic degradation. Saccharide side chains of glycoproteins also play important roles as ligands in biological recognition and in the organized distribution of these compounds within multicellular organisms. Carbohydrate-lectin interactions are important, for example, in viral infections and for the recruitment and invasion of leukocytes into injured tissues. Although in a number of processes carbohydrates were revealed to be decisive recognition labels, in other biological selections peptide sequences proved to be the recognized areas.…

Synthetic Tumor-Associated Glycopeptide Antigens from the Tandem Repeat Sequence of the Epithelial Mucin MUC4

2004

In cancer research, the development of vaccines against tumor-associated antigens is of particular interest. Epithelial cells express mucin type glycoproteins, which are extensively O-glycosylated. In case of cancer, the expression of these mucins is increased, and their carbohydrate side chains show an aberrant glycosylation pattern. A set of single and double glycosylated hexadecapeptides representing the tandem repeat sequence of the epithelial mucin MUC4 carrying different tumor-associated carbohydrate antigens was prepared by sequential solid-phase glycopeptide synthesis. The crucial glycosyl amino acid building blocks containing the T N , T, sialyl-T N and (2,6)-sialyl-T antigens were…

ChemInform Abstract: Synthesis of TN and T Antigen Glycopeptide Sequences of Tumor- Associated MUC-1 Using S-Pent-4-enyl Thioglycosides.

2010

The synthesis of glycopeptides 34 and 38 with tumor associated TN and T antigen structure containing a partial sequence of the tandem repeat unit of the polymorphic epithelial mucin MUC-1 were achieved via fragment condensations. Electrophilic activation of S-pent-4-enyl thioglycosides was appiled for the construction of O-glycosyl amino and saccharide building blocks.

Synthetic Glycopeptides of the Tandem Repeat Sequence of the Epithelial Mucin MUC4 with Tumour-associated Carbohydrate Antigens

2004

Glycohexadecapeptides representing the tandem repeat sequence of the epithelial mucin MUC4 were prepared by applying a solid-phase methodology. The required glycosyl amino acid building blocks containing the tumour-associated saccharide antigens T N -, T,- sialyl-T N , (2,6)- and (2,3)-sialyl-T were synthesized according to a straightforward biomimetic strategy by stepwise extension of the saccharide side chain of a Fmoc-protected galactosamine threonine tert-butyl ester.

Inside Cover: Antibody Induction Directed against the Tumor-Associated MUC4 Glycoprotein (ChemBioChem 6/2015)

2015

Chemoselective Removal of Protecting Groups from O-Glycosyl Amino Acid and Peptide (Methoxyethoxy)ethyl Esters Using Lipases and Papain

1996

The selective C-terminal deprotection of O-glycopeptide (methoxyethoxy)ethyl esters is achieved under mild conditions (pH 6.6, 37 degrees C) by enzymatic hydrolysis using papain or lipase M from Mucor javanicus to give building blocks useful for chain-extending glycopeptide synthesis. On the other hand, the selective removal of acetyl protecting groups from the saccharide portion of glycopeptides is accomplished by alternative enzymatic hydrolysis with lipase WG from wheat germ to furnish model substrates for enzymatic glycosyl transfer reactions in order to extend the carbohydrate side chain of these conjugates.