Search results for "Carbohydrate"
showing 10 items of 882 documents
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…
Combinatorial synthesis of amino acid- and peptide-carbohydrate conjugates on solid phase
2004
Carbohydrates are useful polyfunctional scaffold molecules which allow the selective attachment of a number of different side chains. The combinatorial solid phase synthesis of diverse amino acid or peptide conjugates of a polyfunctional glucose scaffold based on a set of selectively removable and orthogonally stable protecting groups is described. The resulting carbohydrate-peptide hybrids constitute potential turn mimetics.
Does catalase play a role in Adriamycin induced cardiotoxicity?
1980
Summary Adriamycin causes an increase of lipid peroxidation in mouse cardiac homogenates that is dependent on the concentration of the antiblastic. The same phenomenon is not observed in the hearts of mice treated with an elevated dose of Adriamycin in which, conversely, an increase of the antioxidizing enzyme catalase was noticed. The significance of these findings is discussed with relationship to the hypothesis of an enhanced free radicals formation at the basis of Adriamycin induced cardiotoxicity.
Behavior of carbohydrate-based material in black liquor during heating
2004
One industrial softwood Kraft black liquor was heat-treated (at 175 ?C and 190 ?C for 15-60 min) together with laboratory-made soda-AQ (wheat straw and reed canary grass) and Kraft (reed canary grass) black liquors (at 190 ?C for 30 min). The feedstock black liquors were characterized with respect to their polysaccharide (mainly xylem) and aliphatic carboxylic acid contents before and after the heat treatments. It was noted that, due to the higher amount of polysaccharides in the non-wood black liquors (8.2-16.6% of d.s) compared to that in the softwood black liquor (1.4% of d.s), the heat treatment in the former case resulted in a 5-30% increase in the amount of aliphatic acids formed by v…
IR-spectroscopic studies of Zymomonas mobilis and levan precipitate
2002
Abstract The mid-infrared (mid-IR) absorption spectra of Zymomonas mobilis 113 “S” bacterial biomass grown in sucrose or glucose medium, and levan precipitate in the fingerprint region were studied. IR-qualitative and quantitative analyses were carried out. The principal component concentration changes in Z. mobilis biomass at different growth phases showed that protein concentration was higher in case of glucose-based medium, but the total carbohydrate concentration was higher if grown in sucrose-based medium. Low concentration of intracellular carbohydrates was a characteristic parameter of levan-producing Z. mobilis cells. It was shown that during 2-month storage of Z. mobilis inoculum i…
Synthesis of fluorinated Thomsen-Friedenreich antigens: direct deoxyfluorination of αGalNAc-threonine tert-butyl esters.
2011
Selectively 6-fluorinated analogs of the tumor-associated T(N) antigen Fmoc-Thr(α-O-GalNAc)-OtBu can be efficiently prepared using DAST-mediated de(hydr)oxyfluorination reactions of preformed and orthogonally protected glycosyl amino esters without affecting the labile protecting groups and O-glycosidic linkages. The resulting mono- and difluorinated T(N) analogs are interesting building blocks for non-hydrolyzable mucin-type antigen mimetics, as illustrated by the unprecedented synthesis of two different multiply fluorinated Thomsen-Friedenreich derivatives. The reported deoxyfluoro antigen analogs represent important functional probes for carbohydrate-binding proteins and glycosyl-process…
Capillary column gas chromatographic identification of sugars in honey as trimethylsilyl derivatives.
1987
A method for identifying carbohydrates (mono-, di- and trisaccharides) in honey is presented. It is based on the separate preparation of both trimethylsilyl ethers and oxime trimethylsilyl ethers of the sugars followed by their gas chromatographic separation on a fused-silica capillary column coated with OV-101 using temperature programming. From the two chromatograms, the number of peaks given by each derivatized sugar, their relative retention times and peak-area ratios are used for identification. The identities of two unidentified trisaccharide peaks are considered. Quantitative applications to honey sugar analysis are discussed.
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.
ChemInform Abstract: Oligosaccharide Synthesis via Electrophile-Induced Activation of Glycosyl-N-allylcarbamates.
2010
Abstract Glycosyl-N-allyl carbamates, obtained by reaction of anomerically unprotected saccharides with allyl isocyanate, can be activated by an electrophile-induced cyclisation and reacted with glycosyl acceptors to form the corresponding oligosaccharides By this method the mucin core 2 trisaccharide2 has successfully been synthesized. Due to the mild glycosylation conditions even 1-O-acetyl protected glycosyl acceptors can be used. This was demonstrated in the synthesis of a 1,6-linked glucosyl trisaccharide whereby a reptitious glycosylation strategy could be applied. 1. Dedicated to the memory of Professor Akira Hasegawa.
Aggregation of sponge cells. Isolation and characterization of an inhibitor of aggregation receptor from the cell surface.
1979
From the cell membranes of the sponge Geodia cydonium a component was isolated and purified which inhibits the aggregation factor isolated from the same source; the component was termed anti-aggregation receptor. This molecule was characterized as a glycoprotein (54% neutral carbohydrate) and its molecular weight is in the range of 180,000 One biological site of the anti-aggregation receptor was determined to be D-galactose. Indirect evidence presented seems to indicate that this molecule is present in an active form in aggregation-deficient cells and absent in aggregation-susceptible cells.