Search results for "glycoside"
showing 10 items of 296 documents
Modulation Theory of Adhesion: Role of the Ectoenzymes Glycosidase and Glycosyltransferase
1986
It is amazing, but still plausible, that in all animal systems hitherto studied there is only one basic principle by which cell-cell recognition occurs. From sponges to higher eukaryotes there is only a small number of cell adhesion molecules which are involved in cell-cell adhesion. Specificities and histogenetic patterning are achieved by modulating processes acting on cell adhesion molecules. In sponges (secondary aggregation system) and in other eukaryotes, the activity and function of cell adhesion molecules are assumed to be modulated by enzymatic processes (glycosylation and deglycosylation). Strong evidence from experiments with sponges is available which indicates that modulation c…
The yeastWickerhamomyces anomalusAS1 secretes a multifunctional exo-β-1,3-glucanase with implications for winemaking
2014
A multifunctional exo-β-1,3-glucanase (WaExg2) was purified from the culture supernatant of the yeast Wickerhamomyces anomalus AS1. The enzyme was identified by mass spectroscopic analysis of tryptic peptide fragments and the encoding gene WaEXG2 was sequenced. The latter codes for a protein of 427 amino acids, beginning with a probable signal peptide (17 aa) for secretion. The mature protein has a molecular mass of 47 456 Da with a calculated pI of 4.84. The somewhat higher mass of the protein in SDS–PAGE might be due to bound carbohydrates. Presumptive disulphide bridges confer a high compactness to the molecule. This explains the apparent smaller molecular mass (35 kDa) of the native enz…
Isolierung und Charakterisierung eines Dihydroflavonols bei dem Laubmoos Georgia pellucida (L.) Rabh
1977
Summary By means of paper chromatography a dihydroflavonol was isolated from the methanolic extract of the moss Georgia pellucida and partially characterized. It has the chromatographic and spectral characteristics of a 5-deoxydihydroflavonol glycoside with B-ring orthodihydroxyl group.
Coupling of the guanosine glycosidic bond conformation and the ribonucleotide cleavage reaction: implications for barnase catalysis.
2007
To examine the possible relationship of guanine-dependent GpA conformations with ribonucleotide cleavage, two potential of mean force (PMF) calculations were performed in aqueous solution. In the first calculation, the guanosine glycosidic (Gχ) angle was used as the reaction coordinate, and computations were performed on two GpA ionic species: protonated (neutral) or deprotonated (negatively charged) guanosine ribose O2 ′. Similar energetic profiles featuring two minima corresponding to the anti and syn Gχ regions were obtained for both ionic forms. For both forms the anti conformation was more stable than the syn, and barriers of ∼4 kcal/mol were obtained for the anti → syn transition. Str…
Determination of soyasaponins I and βg in raw and cooked legumes by solid phase extraction (SPE) coupled to liquid chromatography (LC)-mass spectrome…
2013
Legumes contain a rich variety of phytochemicals as soyasaponins, triterpenoidal glycosides that possess multiple health-promoting properties, such as lowering of cholesterol. In this work, the quantification of soyasaponins I and βg in 60 raw and cooked legumes by using a solid phase extraction (SPE) coupled to a liquid chromatography (LC)-mass spectrometry (MS) method was carried out. Results showed that lentils are a good source of soyasaponins, with a content of soyasaponin I that ranged from 636 to 735 mg kg(-1) and of soyasaponin βg from 672 to 1807 mg kg(-1). The cooking process produced a small loss of soyasaponins in water, that is, 4.8-8.7%, and partially converted soyasaponin βg …
d-Glucose as a multivalent chiral scaffold for combinatorial chemistry
2002
Due to their high density of functional groups and their availability in a variety of diastereomeric forms, monosaccharides are considered attractive scaffolds for combinatorial chemistry that allow the attachment and defined spatial alignment of up to five different pharmacophoric groups. For their application in combinatorial syntheses on solid phase, a set of selectively removable hydroxy protecting groups in combination with a cleavable anchor is required. Herein, we report on the construction and use of a versatile multivalent glucose building block for parallel synthesis on the solid phase.
New Acylated Presenegenin Saponins from Two Species ofMuraltia
2004
Six new acylated bisdesmosidic triterpene glycosides 1–6 were isolated from the roots of Muraltia heisteria (L.) DC., as three inseparable mixtures 1/2, 3/4, and 5/6 of the (E)- and (Z)-3,4,5-trimethoxycinnamoyl derivatives. The compound pair 1/2 along with four known saponins were also isolated from the roots of Muraltia satureioides DC. Their structures were elucidated mainly by spectroscopic experiments including 2D-NMR techniques as 3-O-(β-D-glucopyranosyl)presenegenin 28-{O-β-D-apiofuranosyl-(13)-O-[β-D-xylopyranosyl-(14)]-O-α-L-rhamnopyranosyl-(12)-O-[6-O-acetyl-β-D-galactopyranosyl-(13)]-4-O-[(E)-3,4,5-trimethoxycinnamoyl]-β-D-fucopyranosyl} ester (1) and its (Z)-isomer 2, 3-O-(β-D-g…
Oplopanone derivatives monoterpene glycosides from Artemisia sieberi
1993
Abstract The aerial parts of Artemisia sieberi yielded three new oplopanone derivatives, three new monoterpene glycosides, a new germacrane alcohol and a monoterpene acid related to nerolidol.
Presenegenin Glycosides from Securidaca welwitschii
2010
) Centre de Recherche Phytochimique, Universite´ de Lie`ge, Institut de Chimie-B6, Sart Tilman,B-4000-Lie`ge IThe five new presenegenin glycosides 1–5 were isolated from Securidaca welwitschii, together withone known sucrose diester. Compounds 1–4 were obtained as pairs of inseparable (E)/(Z)-isomers of a3,4-dimethoxycinnamoyl derivative, i.e., 1/2 and 3/4. Their structures were elucidated mainly by 2D-NMR techniques and mass spectrometry as 3-O-(b-d-glucopyranosyl)presenegenin 28-{O-b-d-xylopyr-anosyl-(1!4)-O-a-l-rhamnopyranosyl-(1!2)-O-[b-d-glucopyranosyl-(1!3)]-4-O-[(E)-3,4-dimeth-oxycinnamoyl]-b-d-fucopyranosyl} ester (1) and its (Z)-isomer 2, 3-O-(b-d-glucopyranosyl)presenege-nin 28-{O…
ChemInform Abstract: Glycoside Synthesis via Electrophile-Induced Activation of N-Allyl Carbamates.
2010
Abstract O-Benzyl-, O-acyl-, N-acyl- and isopropylidene-protected glycosyl N-allylcarbamates, obtained from anomerically unprotected monosaccharides and allyl isocyanate, are activated by an electrophile-induced cyclisation and react with hydroxyl compounds to form the corresponding glycosides.