- Highly efficient chemoenzymatic synthesis of β1-4-linked galactosides with promiscuous bacterial β1-4-galactosyltransferases
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Two bacterial β1-4-galactosyltransferases, NmLgtB and Hp1-4GalT, exhibit promiscuous and complementary acceptor substrate specificity. They have been used in an efficient one-pot multienzyme system to synthesize LacNAc, lactose, and their derivatives including those containing negatively charged 6-O-sulfated GlcNAc and C2-substituted GlcNAc or Glc, from monosaccharide derivatives and inexpensive Glc-1-P.
- Lau, Kam,Thon, Vireak,Yu, Hai,Ding, Li,Chen, Yi,Muthana, Musleh M.,Wong, Denton,Huang, Ronald,Chen, Xi
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- Trypanosoma cruzi trans-sialidase alternative substrates: Study of the effect of substitution in C-6 in benzyl β-lactoside
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Trypanosoma cruzi trans-sialidase (TcTS) is a cell surface protein that participates in the adhesion and invasion mechanisms of the parasite into the host cells, making it an attractive target for inhibitors design. In order to contribute to the knowledge of the interaction between TcTS and their acceptor substrates, we designed and synthesized a library of 20 benzyl lactosides substituted in C-6 of the glucose residue with a series of 1,2,3-triazole derivatives containing different aromatic substituents in the C-4 position. The library was prepared by alkyne-azide cycloaddition reaction catalyzed by Cu(I) (“click chemistry”) between a benzyl β-lactoside functionalized with an azide group in the C-6 position and a series of 2-propargyl phenyl ethers. Herein we analyzed the chromatographic behavior on high performance anion exchange chromatography (HPAEC) of the triazoyl-lactose derivatives and their activity as acceptors of TcTS and inhibitors of the sialylation of N-acetyllactosamine. The triazoyl derivatives were obtained with excellent yields and all of them behaved as moderate alternative substrates. The presence of bulky hydrophobic substituents dramatically increased the retention times in HPAEC but did not affect significantly their acceptor properties toward TcTS.
- Morrone-Pozzuto, Pablo,Uhrig, Maria Laura,Agusti, Rosalia
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supporting information
p. 33 - 45
(2019/05/04)
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- Synthesis of lacto-N-tetraose
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Human milk oligosaccharides (HMOs) are the third largest macromolecular component of breast milk and offer infants numerous health benefits, most of which stem from the development of a healthy microbiome. Characterization, quantification, and chemical de
- Craft, Kelly M.,Townsend, Steven D.
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supporting information
p. 43 - 50
(2017/02/23)
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- Chemoenzymatic Synthesis of a Library of Human Milk Oligosaccharides
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Human milk oligosaccharides (HMOs) are a family of diverse unconjugated glycans that exist in human milk as one of the major components. Characterization, quantification, and biofunctional studies of HMOs remain a great challenge due to their diversity and complexity. The accessibility of a homogeneous HMO library is essential to solve these issues which have beset academia for several decades. In this study, an efficient chemoenzymatic strategy, namely core synthesis/enzymatic extension (CSEE), for rapid production of diverse HMOs was reported. On the basis of 3 versatile building blocks, 3 core structures were chemically synthesized via consistent use of oligosaccharyl thioether and oligosaccharyl bromide as glycosylation donors in a convergent fragment coupling strategy. Each of these core structures was then extended to up to 11 HMOs by 4 robust glycosyltransferases. A library of 31 HMOs were chemoenzymatically synthesized and characterized by MS and NMR. CSEE indeed provides a practical approach to harvest structurally defined HMOs for various applications.
- Xiao, Zhongying,Guo, Yuxi,Liu, Yunpeng,Li, Lei,Zhang, Qing,Wen, Liuqing,Wang, Xuan,Kondengaden, Shukkoor Muhammed,Wu, Zhigang,Zhou, Jun,Cao, Xuefeng,Li, Xu,Ma, Cheng,Wang, Peng George
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p. 5851 - 5865
(2016/07/23)
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- Synthesis and biological evaluation of α-galactosylceramide (KRN7000) and isoglobotrihexosylceramide (iGb3)
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Glycoceramides can activate NKT cells by binding with CD1d to produce IFN-γ, IL-4, and other cytokines. An efficient synthetic pathway for α-galactosylceramide (KRN7000) was established by coupling a protected galactose donor to a properly protected ceramide. During the investigation, it was discovered that when the ceramide was protected with benzyl groups, only β-galactosylceramide was produced from the glycosylation reaction. In contrast, the ceramide with benzoyl protecting groups produced α-galactosylceramide. Isoglobotrihexosylceramide (iGb3) was prepared by glycosylation of Galα1-3Galβ1-4Glc donor with 2-azido-sphingosine in high yield. Biological assays on the synthetic KRN7000 and iGb3 were performed using human and murine iNKT cell clones or hybridomas.
- Xia, Chengfeng,Yao, Qingjia,Schuemann, Jens,Rossy, Emmanuel,Chen, Wenlan,Zhu, Lizhi,Zhang, Wenpeng,De Libero, Gennaro,Wang, Peng George
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p. 2195 - 2199
(2007/10/03)
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- Simple preparations of alkyl and cycloalkyl α-glycosides of maltose, cellobiose, and lactose
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Alkyl, cycloalkyl, allyl, 4-pentenyl, and benzyl α-glycosides of maltose, cellobiose, and lactose were prepared via direct reaction of the free bioses with a binary AcBr-AcOH system, followed by glycosidation with alcohol using FeCl3 in MeNO2 or CH2Cl2, Zemple?n deacetylation, and the chromatographic resolution of the mixture. The respective β-biosides were obtained via the glycosidation in MeCN. Alkyl, cycloalkyl, allyl, 4-pentenyl, and benzyl α-glycosides of maltose, cellobiose, and lactose were prepared (17-77% yield; α/β = 70/30-96/4) via a direct reaction of the free disaccharides with a binary AcBr-AcOH mixture, followed by glycosidation with alcohol using FeCl3 in MeNO2 or CH2Cl2, Zemple?n deacetylation, and resolution of the anomeric mixture of glycosides by chromatography. Using MeCN as solvent for the glycosidation step, the corresponding β-biosides were also prepared (16-61% yield; α/β = 25/75-5/95).
- Koto, Shinkiti,Hirooka, Motoko,Tashiro, Takako,Sakashita, Motokazu,Hatachi, Masaharu,Kono, Takayuki,Shimizu, Miho,Yoshida, Nahoko,Kurasawa, Sayaka,Sakuma, Natsuko,Sawazaki, Sunao,Takeuchi, Akihiro,Shoya, Naomi,Nakamura, Emi
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p. 2415 - 2424
(2007/10/03)
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- Fibrinogen-coated particles for therapeutic use
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The invention provides a particle comprising fibrinogen bound on the surface of an albumin matrix, wherein said particle is capable of coaggregation with platelet, and of aggregation in a solution containing soluble fibrinogen at a concentration of soluble fibrinogen not capable by it self of formation of a clot upon activation by thrombin.
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- Non-crosslinked protein particles for therapeutic and diagnostic use
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Albumin particles in the nanometer and micrometer size range in an aqueous suspension are rendered stable against resolubilization without the aid of a crosslinking agent and without denaturation, by the incorporation of a stabilizing agent in the particle composition. Particles which are primarily albumin in the nanometer and micrometer size range in an aqueous suspension are rendered stable against resolublization by the incorporation of a reducing agent, oxidizing agent, hydrogen-accepting molecule, high molecular weight polymer, sulfur-containing ring compound or combinations thereof.
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- Non-crosslinked protein particles for therapeutic and diagnostic use
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Albumin particles in the nanometer and micrometer size range in an aqueous suspension are rendered stable against resolubilization without the aid of a crosslinking agent and without denaturation, by the incorporation of hemoglobin in the particle composition. Particles which are primarily hemoglobin in the nanometer and micrometer size range in an aqueous suspension are rendered stable against aggregation by the incorporation of either albumin, surface active agents or gelatin.
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- Glycosyl Imidates, 42.- Selectively Protected Lactose and 2-Azido Lactose, Building Blocks for Glycolipid Synthesis
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Performing regioselective alkylation at 3'-OH of benzyl β-lactoside 1 by the stannylation method we prepared the 3'-OH- and 4'-OH-unprotected lactose derivatives 5 and 10 and the 4'-OH-unprotected lactose derivative 9 containing a different protecting gro
- Jung, Karl-Heinz,Hoch, Monika,Schmidt, Richard R.
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p. 1099 - 1106
(2007/10/02)
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- Total synthesis of globotriaosyl-E and Z-ceramides and isoglobotriaosyl-E-ceramide.
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Stereoselective, total synthesis of O-alpha-D-galactopyranosyl-(1----4) -O-beta-D-galactopyranosyl-(1----4)-O-beta-D-glucopyranosyl-(1----1)-N -tetracosanoyl-[2S,3R,4E (and 4Z)]-sphingenine and O-alpha-D -galactopyranosyl-(1----3)-O-beta-D-galactopyranosyl-(1----4)-O-beta-D -glucopyranosyl-(1----1)-N-tetracosanoyl-(2S,3R,4E)-sphin gen ine was achieved by using O-(2,3,4,6-tetra-O-acetyl-alpha-D-galactopyranosyl) -(1----4)-O-(2,3,6-tri-O-acetyl-beta-D-galactopyranosyl)-(1----4)-2,3,6- tri-O-acetyl-alpha-D-glucopyranosyl trichloroacetimidate, O-(2,3,4,6-tetra-O-acetyl-alpha-D-galactopyranosyl) -(1----4)-O-(2,3,6-tri-O-acetyl-beta-D-galactopyranosyl)-(1----4)-2,3,6- tri-O-acetyl-alpha (and beta)-D-glucopyranosyl fluoride, and O-(2,3,4,6-tetra-O-acetyl-alpha-D -galactopyranosyl)-(1----3)-O-(2,3,6-tri-O-acetyl-beta-D-galactopyran osyl)-(1----4)-2,3,6-tri-O-acetyl-alpha-D-glucopyranosyl trichloroacetimidate.
- Koike,Sugimoto,Sato,Ito,Nakahara,Ogawa
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p. 189 - 208
(2007/10/02)
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- THE ACETONATION OF LACTOSE AND BENZYL β-LACTOSIDE WITH 2-METHOXYPROPENE
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The acetonation of lactose with 2-methoxypropene afforded 4,6-O-isopropylidene lactose (2) and a diacetal which, after acetylation, gave an α,β-anomeric mixture of 1,2,6,3'-tetra-O-acetyl-3,2':4',6'-di-O-isopropylidene lactose (4).Acetonation of benzyl β-
- Alonso-Lopez, Manuel,Barbat, Joelle,Fanton, Elizabeth,Fernandez-Mayoralas, Alfonso,Gelas, Jacques,et al.
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p. 1169 - 1176
(2007/10/02)
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