Topic
Pyranose
About: Pyranose is a research topic. Over the lifetime, 1619 publications have been published within this topic receiving 35348 citations. The topic is also known as: pyranoses & hexopyranose.
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TL;DR: It is proposed that oxidation of Phe454, which is located at the flexible active-site loop of TmPOx, is the first and main step in the inactivation of T mPOx by hydrogen peroxide.
Abstract: The flavin-dependent enzyme pyranose oxidase catalyses the oxidation of several pyranose sugars at position C-2. In a second reaction step, oxygen is reduced to hydrogen peroxide. POx is of interest for biocatalytic carbohydrate oxidations, yet it was found that the enzyme is rapidly inactivated under turnover conditions. We studied pyranose oxidase from Trametes multicolor (TmPOx) inactivated either during glucose oxidation or by exogenous hydrogen peroxide using mass spectrometry. MALDI-MS experiments of proteolytic fragments of inactivated TmPOx showed several peptides with a mass increase of 16 or 32 Da indicating oxidation of certain amino acids. Most of these fragments contain at least one methionine residue, which most likely is oxidised by hydrogen peroxide. One peptide fragment that did not contain any amino acid residue that is likely to be oxidised by hydrogen peroxide (DAFSYGAVQQSIDSR) was studied in detail by LC-ESI-MS/MS, which showed a +16 Da mass increase for Phe454. We propose that oxidation of Phe454, which is located at the flexible active-site loop of TmPOx, is the first and main step in the inactivation of TmPOx by hydrogen peroxide. Oxidation of methionine residues might then further contribute to the complete inactivation of the enzyme.
6 citations
TL;DR: In this paper, the synthesis and conformation of 1,2cis-Pentopyranosyl Azides are discussed in terms of 4C1(D)⇌1C4(D)-Konformationsgleichte in Losung diskutiert and with verwandten Pyranosederivaten verglichen.
6 citations
TL;DR: In this article, the pyranose radicals are formed with localized unpaired electrons in positions 1 and 4 of the Pyranoses ring, the formation of which is accompanied by the rupture of the glycoside bond.
Abstract: 1
On gamma irradiation of cellulose radicals are formed with localized unpaired electrons in positions 1 and 4 of the pyranose ring, the formation of which is accompanied by rupture of the glycoside bond
2
Thermal transformations of these radicals cause their degradation and take place with formation of allyl type radicals
6 citations
Patent•
11 Oct 1983TL;DR: In this paper, 1-deoxy-D-mannopyranosides are used as inhibitors of antigen-specific T-cell proliferation and delayed-type hypersensitivity reactions.
Abstract: The invention disclosed herein relates to novel 1-deoxyglycosides, preferably 1-deoxy-D-mannopyranosides and 1-deoxy-L-rhamnopyranosides, having in the 1-position of the pyranose ring an aralkylthio/aralkenylthio, aralkyloxy/aralkenyloxy or aralkanoylamino/aralkenoylamino substituent; and to novel processes for preparing these 1-substituted-1-deoxyglycosides starting with the corresponding tetra-O-acetylglycopyranosyl bromide or amine. The 6-hydroxy group of 1-substituted-1 deoxyglycopyranosides can also be replaced by other functional groups. These aralkylthio/aralkenylthio, aralkyloxy/aralkenyloxy and aralkanoylamino/aralkenoylamino 1-deoxyglycosides are potent inhibitors of antigen-specific T-cell proliferation and are also useful as inhibitors of delayed-type hypersensitivity reactions.
6 citations
TL;DR: Furanose was found by the spectral methods to be preponderant in the equilibrated solutions of coriose and sedoheptulose, while pyranose was shown to be the main constituent in Equilibria DL-gluco-3-heltulose and D-ido-3heptule as discussed by the authors.
Abstract: Furanose was found by the spectral methods to be preponderant in the equilibrated solutions of coriose and sedoheptulose, while pyranose was shown to be the main constituent in equilibrated DL-gluco-3-heptulose and D-ido-3-heptulose. These examples show stableness of five-membered ring having three hydroxyl groups vic and cis to each other, relative to six-membered ring having 1, 3-diaxial hydroxyl groups.
6 citations