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Peter H. Seeberger - One of the best experts on this subject based on the ideXlab platform.
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synthesis of photolabile protecting group ppg protected Uronic Acid building blocks applications in carbohydrate synthesis with the assistance of a continuous flow photoreactor
Organic chemistry frontiers, 2019Co-Authors: Varsha Tiwari, Peter H. Seeberger, Adesh Kumar Singh, Priyanka Chaudhary, Jeyakumar KandasamyAbstract:Photolabile protecting group (PPG) protected Uronic Acid building blocks were prepared and used for carbohydrate synthesis. Deprotection of the photolabile protecting group was achieved very efficiently by employing a continuous flow photoreactor under neutral conditions. Many conventional protecting groups were found to be stable during the photo-cleavage of the 2-nitrobenzyl group at 355 nm in methanol.
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de novo synthesis of Uronic Acid building blocks for assembly of heparin oligosaccharides
Chemistry: A European Journal, 2007Co-Authors: Alexander Adibekian, Pascal Bindschadler, Mattie S M Timmer, Christian Noti, Nina Schutzenmeister, Peter H. SeebergerAbstract:An efficient de novo synthesis of Uronic Acid building blocks is described. The synthetic strategy relies on the stereoselective elongation of thioacetal protected dialdehydes 12 a and 17. The dialdehydes are prepared from D-xylose, a cheap and commercially available source. A highly stereoselective MgBr 2 .OEt 2 -mediated Mukaiyama aldol addition to C4-aldehyde 12a is performed to obtain D-glucUronic Acid building block 16, whereas L-idUronic Acid building block 22 is prepared by MgBr 2 .OEt 2 -mediated cyanation of C5-aldehyde 17. Synthesis of a heparin disaccharide demonstrates the utility of the de novo strategy for the assembly of glycosaminoglycan oligosaccharides.
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modular synthesis of heparin oligosaccharides
Chemistry: A European Journal, 2003Co-Authors: Hernan A Orgueira, Remy E J N Litjens, Alessandra Bartolozzi, Peter Schell, Emma R Palmacci, Peter H. SeebergerAbstract:A general, modular strategy for the first completely stereoselective synthesis of defined heparin oligosaccharides is described. Six monosaccharide building blocks (four differentially protected glucosamines, one glucUronic and one idUronic Acid) were utilized to prepare di- and trisaccharide modules in a fully selective fashion. Installation of the α-glucosamine linkage was controlled by placing a conformational constraint on the Uronic Acid glycosyl acceptors thereby establishing a new concept for stereochemical control. Combination of disaccharide modules to form trans-Uronic Acid linkages was completely selective by virtue of C2 participating groups. Coupling reactions between disaccharide modules exhibited sequence dependence. While the union of many glucosamine Uronic Acid disaccharide modules did not meet any problems, certain sequences proved not accessible. Elaboration of glucosamine Uronic Acid disaccharide building blocks to trisaccharide modules by addition of either one additional glucosamine or Uronic Acid allowed for stereoselective access to oligosaccharides as demonstrated on the example of a hexasaccharide resembling the ATIII-binding sequence. Final deprotection and sulfation yielded the fully synthetic heparin oligosaccharides.
Terri A. Camesano - One of the best experts on this subject based on the ideXlab platform.
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adhesion of aureobasidium pullulans is controlled by Uronic Acid based polymers and pullulan
Biomacromolecules, 2005Co-Authors: Jill M. Pouliot, Ian Walton, Matthew Nolenparkhouse, Laila Abulail, Terri A. CamesanoAbstract:Aureobasidium pullulans is a potentially pathogenic microfungus that produces and secretes the polysaccharide pullulan and other biomacromolecules, depending on the microbe's physiological state. The role of these macromolecules in mediating adhesion and attachment were examined. Interfacial forces and adhesion affinities of A. pullulans were probed for early-exponential phase (EEP) and late-exponential phase (LEP) cells, using atomic force microscopy (AFM). Biochemical assays showed that A. pullulans produces both pullulan and a Uronic Acid based polymer. The pullulan is not produced until the LEP, and it can be removed by treatment with pullulanase. Both adhesion forces between the microbe and the AFM tip (silicon nitride) and attachment of the cells to quartz sand grains were controlled by the density of the Uronic Acid polymer. Uronic Acid polymers doubled in density between the EEP and the LEP and were unaffected by the enzyme pullulanase. Retention to quartz in a packed column was quantified using the collision efficiency (alpha), the fraction of collisions between the microbes, and the sand grains, that result in attachment. Adhesion forces and retention on glass were well correlated, with these values being higher for EEP cells (F(adh) = 7.65 +/-4.67 nN; alpha = 1.15) than LEP (F(adh) = 2.94 +/- 0.75; alpha = 0.49) and LEP + pullulanase cells (F(adh) = 2.33 +/-2.01 nN; alpha = 0.43). Steric interactions alone do not describe the adhesion behavior of this fungus, but they do provide information regarding the length and density of the macromolecules studied.
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Adhesion of Aureobasidium pullulans is controlled by Uronic Acid based polymers and pullulan.
Biomacromolecules, 2005Co-Authors: Jill M. Pouliot, Ian Walton, Matthew Nolen-parkhouse, Laila Abu-lail, Terri A. CamesanoAbstract:Aureobasidium pullulans is a potentially pathogenic microfungus that produces and secretes the polysaccharide pullulan and other biomacromolecules, depending on the microbe's physiological state. The role of these macromolecules in mediating adhesion and attachment were examined. Interfacial forces and adhesion affinities of A. pullulans were probed for early-exponential phase (EEP) and late-exponential phase (LEP) cells, using atomic force microscopy (AFM). Biochemical assays showed that A. pullulans produces both pullulan and a Uronic Acid based polymer. The pullulan is not produced until the LEP, and it can be removed by treatment with pullulanase. Both adhesion forces between the microbe and the AFM tip (silicon nitride) and attachment of the cells to quartz sand grains were controlled by the density of the Uronic Acid polymer. Uronic Acid polymers doubled in density between the EEP and the LEP and were unaffected by the enzyme pullulanase. Retention to quartz in a packed column was quantified using t...
F Atmani - One of the best experts on this subject based on the ideXlab platform.
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identification of Uronic Acid rich protein as urinary bikunin the light chain of inter α inhibitor
FEBS Journal, 1996Co-Authors: F Atmani, Jacques Mizon, Saeed R KhanAbstract:Uronic-Acid-rich protein (UAP) is a urinary glycoprotein that inhibits calcium oxalate crystallization in vitro. It shows a structural similarity to bikunin, a component of inter-α-inhibitor (IαI) known for its inhibition of the action of many serine proteinases like trypsin and chymotrypsin. To clarify the relationship between these macromolecules, UAP, IαI, urinary bikunin, and plasma bikunin were purified and studied. Their calcium oxalate crystallization inhibitory activity was assayed before and after treatment with chondroitinase AC and pronase. Their molecular mass was determined by using SDS/PAGE before and after these treatments. Polyclonal bikunin antibody was used on Western blots for immunological identification. The partial amino Acid sequence of UAP before and after chondroitinase treatment was determined. Also, the antitryptic activity of UAP was measured and compared to that of bikunin, which is responsible for the antiprotease activity of IαI. UAP exhibited a strong calcium oxalate crystallization inhibitory activity. IαI and both bikunins were less inhibitory. Chondroitinase AC had no effect on inhibitory activity of these proteins even when their molecular mass changed. However, after pronase treatment, the inhibitory activity of both bikunins and UAP was completely destroyed. The antitryptic activity of UAP was found to be 0.78 U/mg which is lower than that of bikunin which is about 1.9 U/mg. On Western blotting, bikunin antibody immunoreacted with UAP and both urinary and plasma bikunins. Partial amino Acid sequence confirmed the identity of UAP as urinary bikunin.
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characterization of Uronic Acid rich inhibitor of calcium oxalate crystallization isolated from rat urine
Urological Research, 1995Co-Authors: F Atmani, Saeed R KhanAbstract:Human urine contains several macromolecules which inhibit calcium oxalate crystallization. Uronic-Acid-rich protein (UAP), a glycoprotein with a molecular weight of approximately 35 kDa, is one such inhibitor. Here we report the characterization of UAP extracted from rat urine using three chromatographic steps including diethylaminoethanol (DEAE)-Sephacel, Sephacryl S-300 and Mono Q column and compare it with human UAP. The molecular weight of rat UAP (UAPr) is similar to that of human UAP (UAPh), being approximately 35 kDa as estimated by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). Their amino Acid compositions are identical, they contain a high percentage of aspartic and glutamic Acids and they react positively in the carbazole reaction, suggesting that they contain Uronic Acid. The inhibitory activities of UAPh and UAPr were assayed on a calcium oxalate crystallization system in vitro using [45Ca]calcium chloride. Both exert a strong inhibition, suggesting that UAPr, like UAPh, plays an important role in preventing and reducing calcium oxalate crystallization in the urine. On Western blot analysis, both UAPh and UAPr immunoreact with inter-α-trypsin inhibitor (ITI) antibody. Nevertheless, using the Ouchterlony immunodiffusion technique, there was no precipitation line between ITI antibody and UAP. Therefore, we hypothesize that UAP is related to ITI and that they may have the same epitope but are not completely identical. We conclude that UAP belongs to the ITI superfamily of macromolecules which contribute to the regulation of the calcium oxalate crystallization process.
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molecular characteristics of Uronic Acid rich protein a strong inhibitor of calcium oxalate crystallization in vitro
Biochemical and Biophysical Research Communications, 1993Co-Authors: F Atmani, Bernard Lacour, G Strecker, P Parvy, Tilman B Drueke, M DaudonAbstract:Uronic-Acid-rich protein (UAP) is a new urinary macromolecule which strongly inhibits calcium oxalate crystal formation. It is a glycoprotein with a molecular weight of about 35,000 Da, and its carbohydrate content is 8.5%. This inhibitor is composed of two polypeptidic chains crosslinked by chondroitin sulfate. It exhibits partial structural homology with alpha 1-microglobulin. The inhibitory activity seems to be supported by peptidic chains as determined by enzymatic assay.
Jill M. Pouliot - One of the best experts on this subject based on the ideXlab platform.
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adhesion of aureobasidium pullulans is controlled by Uronic Acid based polymers and pullulan
Biomacromolecules, 2005Co-Authors: Jill M. Pouliot, Ian Walton, Matthew Nolenparkhouse, Laila Abulail, Terri A. CamesanoAbstract:Aureobasidium pullulans is a potentially pathogenic microfungus that produces and secretes the polysaccharide pullulan and other biomacromolecules, depending on the microbe's physiological state. The role of these macromolecules in mediating adhesion and attachment were examined. Interfacial forces and adhesion affinities of A. pullulans were probed for early-exponential phase (EEP) and late-exponential phase (LEP) cells, using atomic force microscopy (AFM). Biochemical assays showed that A. pullulans produces both pullulan and a Uronic Acid based polymer. The pullulan is not produced until the LEP, and it can be removed by treatment with pullulanase. Both adhesion forces between the microbe and the AFM tip (silicon nitride) and attachment of the cells to quartz sand grains were controlled by the density of the Uronic Acid polymer. Uronic Acid polymers doubled in density between the EEP and the LEP and were unaffected by the enzyme pullulanase. Retention to quartz in a packed column was quantified using the collision efficiency (alpha), the fraction of collisions between the microbes, and the sand grains, that result in attachment. Adhesion forces and retention on glass were well correlated, with these values being higher for EEP cells (F(adh) = 7.65 +/-4.67 nN; alpha = 1.15) than LEP (F(adh) = 2.94 +/- 0.75; alpha = 0.49) and LEP + pullulanase cells (F(adh) = 2.33 +/-2.01 nN; alpha = 0.43). Steric interactions alone do not describe the adhesion behavior of this fungus, but they do provide information regarding the length and density of the macromolecules studied.
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Adhesion of Aureobasidium pullulans is controlled by Uronic Acid based polymers and pullulan.
Biomacromolecules, 2005Co-Authors: Jill M. Pouliot, Ian Walton, Matthew Nolen-parkhouse, Laila Abu-lail, Terri A. CamesanoAbstract:Aureobasidium pullulans is a potentially pathogenic microfungus that produces and secretes the polysaccharide pullulan and other biomacromolecules, depending on the microbe's physiological state. The role of these macromolecules in mediating adhesion and attachment were examined. Interfacial forces and adhesion affinities of A. pullulans were probed for early-exponential phase (EEP) and late-exponential phase (LEP) cells, using atomic force microscopy (AFM). Biochemical assays showed that A. pullulans produces both pullulan and a Uronic Acid based polymer. The pullulan is not produced until the LEP, and it can be removed by treatment with pullulanase. Both adhesion forces between the microbe and the AFM tip (silicon nitride) and attachment of the cells to quartz sand grains were controlled by the density of the Uronic Acid polymer. Uronic Acid polymers doubled in density between the EEP and the LEP and were unaffected by the enzyme pullulanase. Retention to quartz in a packed column was quantified using t...
Mark Von Itzstein - One of the best experts on this subject based on the ideXlab platform.
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rapid access to Uronic Acid based mimetics of kdn2en from d glucurono 6 3 lactone
Carbohydrate Research, 2000Co-Authors: Pas Florio, Robin J Thomson, Mark Von ItzsteinAbstract:A concise route to novel mimetics of Kdn2en, based on delta4-Uronic Acids, from D-glucurono-6,3-lactone is presented. Uronic Acid-based mimetics in which an aliphatic ether (O-glycoside), a thioether (S-glycoside), or acetamide takes the place of the natural C-6 glycerol sidechain of the sialic Acid were synthesized from the key intermediate, methyl 2,3,4-tri-O-acetyl-alpha-D-glucopyranosyluronate bromide.
