- Deoxyfluoro-d-trehalose (FDTre) analogues as potential PET probes for imaging mycobacterial infection
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Mycobacterium tuberculosis, the etiological agent of human tuberculosis, requires the non-mammalian disaccharide trehalose for growth and virulence. Recently, detectable trehalose analogues have gained attention as probes for studying trehalose metabolism and as potential diagnostic imaging agents for mycobacterial infections. Of particular interest are deoxy-[18F]fluoro-d-trehalose (18F-FDTre) analogues, which have been suggested as possible positron emission tomography (PET) probes for in vivo imaging of M. tuberculosis infection. Here, we report progress toward this objective, including the synthesis and conformational analysis of four non-radioactive deoxy-[19F]fluoro-d-trehalose (19F-FDTre) analogues, as well as evaluation of their uptake by M. smegmatis. The rapid synthesis and purification of several 19F-FDTre analogues was accomplished in high yield using a one-step chemoenzymatic method. Conformational analysis of the 19F-FDTre analogues using NMR and molecular modeling methods showed that fluorine substitution had a negligible effect on the conformation of the native disaccharide, suggesting that fluorinated analogues may be successfully recognized and processed by trehalose metabolic machinery in mycobacteria. To test this hypothesis and to evaluate a possible route for delivery of FDTre probes specifically to mycobacteria, we showed that 19F-FDTre analogues are actively imported into M. smegmatis via the trehalose-specific transporter SugABC-LpqY. Finally, to demonstrate the applicability of these results to the efficient preparation and use of short-lived 18F-FDTre PET radiotracers, we carried out 19F-FDTre synthesis, purification, and administration to M. smegmatis in 1 hour.
- Rundell, Sarah R.,Wagar, Zachary L.,Meints, Lisa M.,Olson, Claire D.,O'Neill, Mara K.,Piligian, Brent F.,Poston, Anne W.,Hood, Robin J.,Woodruff, Peter J.,Swarts, Benjamin M.
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- Chemoenzymatic radiosynthesis of 2-deoxy-2-[18F]fluoro-D-trehalose ([18F]-2-FDTre): A PET radioprobe for in vivo tracing of trehalose metabolism
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Trehalose analogues bearing fluorescent and click chemistry tags have been developed as probes of bacterial trehalose metabolism, but these tools have limitations with respect to in vivo imaging applications. Here, we report the radiosynthesis of the 18F-modified trehalose analogue 2-deoxy-2-[18F]fluoro-D-trehalose ([18F]-2-FDTre), which in principle can be used in conjunction with positron emission tomography (PET) imaging to allow in vivo imaging of trehalose metabolism in various contexts. A chemoenzymatic method employing the thermophilic TreT enzyme from Thermoproteus tenax was used to rapidly (15–20 min), efficiently (70% radiochemical yield; ≥ 95% radiochemical purity), and reproducibly convert the commercially available radiotracer 2-deoxy-2-[18F]fluoro-D-glucose ([18F]-2-FDG) into the target radioprobe [18F]-2-FDTre in a single step; both manual and automated syntheses were performed with similar results. Cellular uptake experiments showed that radiosynthetic [18F]-2-FDTre was metabolized by Mycobacterium smegmatis but not by various mammalian cell lines, pointing to the potential future use of this radioprobe for selective PET imaging of infections caused by trehalose-metabolizing bacterial pathogens such as M. tuberculosis.
- Pe?a-Zalbidea, Santiago,Huang, Ashley Y.-T.,Kavunja, Herbert W.,Salinas, Beatriz,Desco, Manuel,Drake, Christopher,Woodruff, Peter J.,Vaquero, Juan J.,Swarts, Benjamin M.
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- Chemoenzymatic synthesis of trehalose analogues: Rapid access to chemical probes for investigating mycobacteria
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Trehalose analogues are emerging as valuable tools for investigating Mycobacterium tuberculosis, but progress in this area is slow due to the difficulty in synthesizing these compounds. Here, we report a chemoenzymatic synthesis of trehalose analogues that employs the heat-stable enzyme trehalose synthase (TreT) from the hyperthermophile Thermoproteus tenax. By using TreT, various trehalose analogues were prepared quickly (1 h) in high yield (up to >99 % by HPLC) in a single step from readily available glucose analogues. To demonstrate the utility of this method in mycobacteria research, we performed a simple "one-pot metabolic labeling" experiment that accomplished probe synthesis, metabolic labeling, and imaging of M. smegmatis in a single day with only TreT and commercially available materials. Trehalose tools for TB: A one-step chemoenzymatic method for the rapid and efficient synthesis of trehalose analogues was developed. This method enabled facile preparation and administration of a trehalose-based probe for detecting mycobacteria, which might enable the development of new diagnostic tools for tuberculosis (TB) research.
- Urbanek, Bailey L.,Wing, Douglas C.,Haislop, Krystal S.,Hamel, Chelsey J.,Kalscheuer, Rainer,Woodruff, Peter J.,Swarts, Benjamin M.
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- Enzymatically derived sugar-containing self-assembled organogels with nanostructured morphologies
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The long and short of it: A regioselective enzyme-catalyzed acylation of the disaccharide trehalose generated a family of low-molecular-weight gelators with unprecedented properties. The selectivity of enzymatic catalysis enables direct control over gelation properties by simply varying the acyl-chain length to give gelation in solvents ranging from the highly hydrophilic acetonitrile to the highly hydrophobic cyclohexane. (Chemical Equation Presented).
- John, George,Zhu, Guangyu,Li, Jun,Dordick, Jonathan S.
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- Construction of a recombinant thermostable β-amylase-trehalose synthase bifunctional enzyme for facilitating the conversion of starch to trehalose
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A fusion gene that encoded a polypeptide of 1495 amino acids was constructed from the β-amylase (BA) gene of Clostridium thermosulfurogenes and trehalose synthase (TS) gene of Thermus thermophilus. The fused gene was overexpressed in Escherichia coli, and a recombinant bifunctional fusion protein with BA at the N-terminal (BATS) or C-terminal (TSBA) of TS having both β-amylase and trehalose synthase activities with an apparent molecular mass of 164 kDa was obtained. BATS or TSBA catalyzes the sequential reaction in which maltose is formed from starch and then is converted into trehalose. The Km values of the BATS and TSBA fusion enzymes for the reaction from starch to trehalose were smaller than those of an equimolar mixture of BA and TS (BA/TS). On the other hand, the kcat value of BATS approximated that of the BA/TS mixture, but that of TSBA exceeded it. TSBA showed much higher sequential catalytic efficiency than the separately expressed BA/TS mixture. The catalytic efficiency of TSBA or BATS was 3.4 or 2.4 times higher, respectively, than that of a mixture of individual enzymes, showing the kinetic advantage of the fusion enzyme. The thermal stability readings of the recombinant fusion enzymes BATS and TSBA were better than that of the mixture of individual recombinant enzymes. These results apparently demonstrate that fusion enzymes catalyzing sequential reactions have kinetic advantages over a mixture of both enzymes.
- Wang, Jia-Hung,Tsai, Meng-Yin,Lee, Guan-Chiun,Shaw, Jei-Fu
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- Anomeric Selectivity of Trehalose Transferase with Rare l -Sugars
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Retaining LeLoir glycosyltransferases catalyze the formation of glycosidic bonds between nucleotide sugar donors and carbohydrate acceptors. The anomeric selectivity of trehalose transferase from Thermoproteus uzoniensis was investigated for both d- and l-glycopyranose acceptors. The enzyme couples a wide range of carbohydrates, yielding trehalose analogues with conversion and enantioselectivity of >98%. The anomeric selectivity inverts from α,α-(1 → 1)-glycosidic bonds for d-glycopyranose acceptors to α,β-(1 → 1)-glycosidic bonds for l-glycopyranose acceptors, while (S)-selectivity was retained for both types of sugar acceptors. Comparison of protein crystal structures of trehalose transferase in complex with α,α-trehalose and an unnatural α,β-trehalose analogue highlighted the mechanistic rationale for the observed inversion of anomeric selectivity.
- Bento, Isabel,Hagedoorn, Peter-Leon,Hanefeld, Ulf,Jeffries, Cy M.,Laustsen, Jesper U.,Marsden, Stefan R.,Mestrom, Luuk,Svergun, Dmitri I.,Van Der Eijk, Hessel
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p. 8835 - 8839
(2020/09/18)
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- COMPOSITIONS AND METHODS
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A method of determining whether an individual is infected with a mycobacterial disease, the method comprising: (a) providing a system which comprises an antigen; (b) contacting the system with a sample obtained from the individual; and (c) detecting the presence or absence of binding of a biomarker in the sample with the antigen; wherein the antigen is a mycolic acid wax ester derived antigen.
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- Structures of trehalose-6-phosphate phosphatase from pathogenic fungi reveal the mechanisms of substrate recognition and catalysis
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Trehalose is a disaccharide essential for the survival and virulence of pathogenic fungi. The biosynthesis of trehalose requires trehalose-6-phosphate synthase, Tps1, and trehalose-6-phosphate phosphatase, Tps2. Here, we report the structures of the N-terminal domain of Tps2 (Tps2NTD) from Candida albicans, a transition-state complex of the Tps2 C-terminal trehalose-6-phosphate phosphatase domain (Tps2PD) bound to BeF3 and trehalose, and catalytically dead Tps2PD(D24N) from Cryptococcus neoformans bound to trehalose-6-phosphate (T6P). The Tps2NTD closely resembles the structure of Tps1 but lacks any catalytic activity. The Tps2PD-BeF3 -trehalose and Tps2PD(D24N)-T6P complex structures reveal a "closed" conformation that is effected by extensive interactions between each trehalose hydroxyl group and residues of the cap and core domains of the protein, thereby providing exquisite substrate specificity. Disruption of any of the direct substrate-protein residue interactions leads to significant or complete loss of phosphatase activity. Notably, the Tps2PD-BeF3 -trehalose complex structure captures an aspartyl-BeF3 covalent adduct, which closely mimics the proposed aspartyl-phosphate intermediate of the phosphatase catalytic cycle. Structures of substrate-free Tps2PD reveal an "open" conformation whereby the cap and core domains separate and visualize the striking conformational changes effected by substrate binding and product release and the role of two hinge regions centered at approximately residues 102-103 and 184-188. Significantly, tps2Δ, tps2NTDAΔ, and tps2D705N strains are unable to grow at elevated temperatures. Combined, these studies provide a deeper understanding of the substrate recognition and catalytic mechanism of Tps2 and provide a structural basis for the future design of novel antifungal compounds against a target found in three major fungal pathogens.
- Miaoa, Yi,Tenorb, Jennifer L.,Toffalettib, Dena L.,Washingtona, Erica J.,Liuc, Jiuyu,Shadrickc, William R.,Schumachera, Maria A.,Leec, Richard E.,Perfectb, John R.,Brennana, Richard G.
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p. 7148 - 7153
(2016/07/07)
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- Simalin A and B: Two new aromatic compounds from the stem bark of Bombax ceiba
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Two new aromatic compounds, simalin A (1) and B (2), along with five known compounds shamiminol (3), (-)-epicatechin-7-O-β-xylopyranoside (4), (-)-catechin-7-O-β-xylopyranoside (5), (+)-isolarisiresinol-9′-O- β-glucopyranoside (6) and (+)-lyoniresinol-9′-O-β- glucopyranoside (7) were isolated from the stem bark of Bombax ceiba. Their structures were elucidated by chemical and spectral methods. Compounds 6 and 7 were isolated for the first time from B. ceiba.
- Joshi, Khem Raj,Devkota, Hari Prasad,Yahara, Shoji
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- Cloning, expression, properties, and functional amino acid residues of new trehalose synthase from Thermomonospora curvata DSM 43183
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A new trehalose synthase (TreS) gene from Thermomonospora curvata DSM 43183 was cloned and expressed in Escherichia coli XL10-Gold. The purified recombinant enzyme (TreS-T.C) could catalyze the reversible interconversion of maltose and trehalose of sucrose into trehalulose without other disaccharides including isomaltulose at an optimum temperature of 35 °C and a pH of 6.5. The Km of TreS-T.C for maltose (96 mM) was lower than those for trehalose (198 mM) and sucrose (164 mM), suggesting that maltose is the optimum substrate. The maximum trehalose and trehalulose yields were 70% and >80%, respectively. Active TreS-T.C is a trimer comprising three identical 60 kDa subunits. Homology modeling analysis revealed that TreS-T.C had a GH13-typical (β/α)8 barrel catalytic domain. Two sites, one determining substrate specificity (L116) and the other affecting product formation (E330), were found near the active center by homology modeling combined with site-directed mutagenesis. TreS-T.C may be used effectively as a potential biocatalyst for the production of trehalose and trehalulose from maltose and sucrose in a one-step reaction, respectively. This study also provides a feasible and effective method for studying functional amino acid residues around TreS without performing crystal structure analysis and high-throughput screening.
- Liang, Jiayuan,Huang, Ribo,Huang, Ying,Wang, Xiaobo,Du, Liqin,Wei, Yutuo
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- COMPOSITIONS CONTAINING SUCRALOSE AND APPLICATION THEREOF
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Novel utilization of sucralose which is a high intense sweetener. Compositions containing sucralose including: sweetening compositions having excellent sweetness qualities based on the characteristics of sucralose; foods with a masked unpleasant smell and unpleasant taste; performance food compositions (viscous food compositions, gel food compositions, emulsified food compositions); foods with improved flavors; preservatives and foods with improved quality of taste; and flavor compositions with improved flavors. Novel utilization of sucralose as a sweetener improver, a masking agent for unpleasant smell/unpleasant taste, a flavor improver, a function improver (viscosity, gelling properties, emulsification properties), a taste characteristic improver, and a flavor improver/enhancer.
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- Pseudoglycosyltransferase catalyzes nonglycosidic C-N coupling in validamycin a biosynthesis
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Glycosyltransferases are ubiquitous in nature. They catalyze a glycosidic bond formation between sugar donors and sugar or nonsugar acceptors to produce oligo/polysaccharides, glycoproteins, glycolipids, glycosylated natural products, and other sugar-containing entities. However, a trehalose 6-phosphate synthase-like protein has been found to catalyze an unprecedented nonglycosidic C-N bond formation in the biosynthesis of the aminocyclitol antibiotic validamycin A. This dedicated 'pseudoglycosyltransferase catalyzes a condensation between GDP-valienol and validamine 7-phosphate to give validoxylamine A 7′-phosphate with net retention of the 'anomeric configuration of the donor cyclitol in the product. The enzyme operates in sequence with a phosphatase, which dephosphorylates validoxylamine A 7′-phosphate to validoxylamine A.
- Asamizu, Shumpei,Yang, Jongtae,Almabruk, Khaled H.,Mahmud, Taifo
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experimental part
p. 12124 - 12135
(2011/10/09)
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- Catalytic reversibility of Pyrococcus horikoshii trehalose synthase: Efficient synthesis of several nucleoside diphosphate glucoses with enzyme recycling
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The trehalose synthase (TreT) from Pyrococcus horikoshii represented reversible catalysis in alternative synthesis of trehalose and nucleoside 5′-diphosphate-glucose (NDP-Glc), depending on the substrates involved. TreT from P. horikoshii had differential preferences on NDP-Glc as a donor for trehalose synthesis, in which guanosine 5′-diphosphate (GDP)-Glc was the most favored in terms of reaction specificity, kcat/Km. Uridine 5′-diphosphate (UDP)- and adenosine 5′-diphosphate (ADP)-Glcs were employed with less preferences. This enzyme reversely cleaved trehalose to transfer the glucosyl moiety to various NDPs, efficiently producing NDP-Glcs. Although ADP-Glc was the least favorable donor, the counterpart, ADP, was the most favorable acceptor for the reverse synthesis of NDP-Glc in k cat/Km. GDP and UDP were less preferred, compared to ADP. In a batch reaction of 12 h, the molar yield of NDP-Glc per NDP used was decreased approximately in the order of ADP-Glc > GDP-Glc > cytidine 5′-diphosphate (CDP)-Glc or UDP-Glc. The overall productivity of the enzyme was largely improved in a gram scale for NDP-Glcs using repetitive batch reactions with enzyme recycling. Thus, it is suggested that TreT from P. horikoshii may be useful for the regeneration of NDP-Glc from NDP, especially for ADP-Glc from ADP, with trehalose as a glucose resource.
- Ryu, Soo-In,Kim, Jeong-Eun,Kim, Eun-Joo,Chung, Seung-Kyung,Lee, Soo-Bok
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experimental part
p. 128 - 134
(2011/09/20)
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- Branched alpha-glucan, alpha-glucosyltransferase which forms the glucan, their preparation and uses
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The present invention has objects to provide a glucan useful as water-soluble dietary fiber, its preparation and uses. The present invention solves the above objects by providing a branched α-glucan, which is constructed by glucose molecules and characterized by methylation analysis as follows: (1) Ratio of 2,3,6-trimethyl-1,4,5-triacetyl-glucitol to 2,3,4-trimethyl-1,5,6-triacetyl-glucitol is in the range of 1:0.6 to 1:4;(2) Total content of 2,3,6-trimethyl-1,4,5-triacetyl-glucitol and 2,3,4-trimethyl-1,5,6-triacetyl-glucitol is 60% or higher in the partially methylated glucitol acetates;(3) Content of 2,4,6-trimethyl-1,3,5-triacetyl-glucitol is 0.5% or higher but less than 10% in the partially methylated glucitol acetates; and(4) Content of 2,4-dimethyl-1,3,5,6-tetraacetyl-glucitol is 0.5% or higher in the partially methylated glucitol acetates; a novel α-glucosyltransferase which forms the branched α-glucan, processes for producing them, and their uses.
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Page/Page column 18-19
(2010/06/11)
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- Catalytic reaction mechanism based on α-secondary deuterium isotope effects in hydrolysis of trehalose by European honeybee trehalase
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Trehalase, an anomer-inverting glycosidase, hydrolyzes only α, α-trehalose in natural substrates to release equimolecular β-glucose and α-glucose. Since the hydrolytic reaction is reversible, α, α-[1, 1′-2H]trehalose is capable of synthesis from [1-2H]glucose through the reverse reaction of trehalase. α-Secondary deuterium kinetic isotope effects (α-SDKIEs) for the hydrolysis of synthesized α, α-[1, 1′-2H]trehalose by honeybee trehalase were measured to examine the catalytic reaction mechanism. Relatively high kH/kD value of 1.53 for α-SDKIEs was observed. The data imply that the catalytic reaction of the trehalase occurs by the oxocarbenium ion intermediate mechanism. In addition, the hydrolytic reaction of glycosidase is discussed from the viewpoint of chemical reactivity for the hydrolysis of acetal in organic chemistry. As to the hydrolytic reaction mechanism of glycosidases, oxocarbenium ion intermediate and nucleophilic displacement mechanisms have been widely recognized, but it is pointed out for the first time that the former mechanism is rational and valid and generally the latter mechanism is unlikely to occur in the hydrolytic reaction of glycosidases.
- Mori, Haruhide,Lee, Jin-Ha,Okuyama, Masayuki,Nishimoto, Mamoru,Ohguchi, Masao,Kim, Doman,Kimura, Atsuo,Chiba, Seiya
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experimental part
p. 2466 - 2473
(2010/08/06)
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- Identification of the essential catalytic residues and selectivity-related residues of maltooligosyltrehalose trehalohydrolase from the thermophilic archaeon Sulfolobus solfataricus ATCC 35092
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Maltooligosyltrehalose trehalohydrolase (MTHase) catalyzes the release of trehalose by cleaving the α-1,4-glucosidic linkage next to the α-1,1-linked terminal disaccharide of maltooligosyltrehalose. Mutations at residues D255, E286, and D380 were constructed to identify the essential catalytic residues of MTHase, while mutations at residues W218, A259, Y328, F355, and R356 were constructed to identify selectivity-related residues of the enzyme. The specific activities of the purified D255A, E286A, and D380A MTHases were only 0.15, 0.09 and 0.01%, respectively, of that of wildtype MTHase, suggesting that these three residues are essential catalytic residues. Compared with wild-type MTHase, A259S, Y328F, F355Y, and R356K MTHases had increased selectivity ratios, which were defined as the ratios of the catalytic efficiencies for glucose formation to those for trehalose formation in the hydrolysis of maltooligosaccharides and maltooligosyltrehaloses, respectively, while W218A and W218F MTHases had decreased selectivity ratios. When starch digestion was carried out at 75°C and wild-type and mutant MTHases were, respectively, used with isoamylase and maltooligosyltrehalose synthase (MTSase), the ratios of initial rates of glucose formation to those of trehalose formation were inversely correlated to the peak trehalose yields.
- Fang, Tsuei-Yun,Tseng, Wen-Chi,Shih, Tong-Yuan,Wang, Mei-Ying
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experimental part
p. 5628 - 5633
(2010/03/23)
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- Protein engineering of Sulfolobus solfataricus maltooligosyltrehalose synthase to alter its selectivity
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Maltooligosyltrehalose synthase (MTSase) is one of the key enzymes involved in trehalose production from starch and catalyzes an intramolecular transglycosylation reaction by converting the α-1,4- to α,α-1,1-glucosidic linkage. Mutations at residues F206, F207, and F405 were constructed to change the selectivity of the enzyme because the changes in selectivity could reduce the side hydrolysis reaction of releasing glucose and thus increase trehalose production from starch. As compared with wild-type MTSase, F405Y and F405M MTSases had decreased ratios of the initial rate of glucose formation to that of trehalose formation in starch digestion at 75°C when wild-type and mutant MTSases were, respectively, used with isoamylase and maltooligosyltrehalose trehalohydrolase (MTHase). The highest trehalose yield from starch digestion was by the mutant MTSase having the lowest initial rate of glucose formation to trehalose formation, and this predicted high trehalose yield better than the ratio of catalytic efficiency for hydrolysis to that for transglycosylation.
- Fang, Tsuei-Yun,Tseng, Wen-Chi,Pan, Ching-Hsing,Chun, Yao-Te,Wang, Mei-Ying
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p. 5588 - 5594
(2008/03/12)
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- Expression, purification, and characterization of the maltooligosyltrehalose trehalohydrolase from the thermophilic archaeon Sulfolobus solfataricus ATCC 35092
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The maltooligosyltrehalose trehalohydrolase (MTHase) mainly cleaves the α-1,4-glucosidic linkage next to the α-1,1-linked terminal disaccharide of maltooligosyltrehalose to produce trehalose and the maltooligosaccharide with lower molecular mass. In this study, the treZ gene encoding MTHase was PCR-cloned from Sulfolobus solfataricus ATCC 35092 and then expressed in Escherichia coli. A high yield of the active wild-type MTHase, 13300 units/g of wet cells, was obtained in the absence of IPTG induction. Wild-type MTHase was purified sequentially using heat treatment, nucleic acid precipitation, and ion-exchange chromatography. The purified wild-type MTHase showed an apparent optimal pH of 5 and an optimal temperature at 85°C. The enzyme was stable at pH values ranging from 3.5 to 11, and the activity was fully retained after a 2-h incubation at 45-85°C. The kcat values of the enzyme for hydrolysis of maltooligosyltrehaloses with degree of polymerization (DP) 4-7 were 193, 1030, 1190, and 1230 s-1, respectively, whereas the kcat values for glucose formation during hydrolysis of DP 4-7 maltooligosaccharides were 5.49, 17.7, 18.2, and 6.01 s-1, respectively. The KM values of the enzyme for hydrolysis of DP 4-7 maltooligosyltrehaloses and those for maltooligosaccharides are similar at the same corresponding DPs. These results suggest that this MTHase could be used to produce trehalose at high temperatures.
- Fang, Tsuei-Yun,Tseng, Wen-Chi,Guo, Meng-Shin,Shih, Tong-Yuan,Hung, Xing-Guang
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p. 7105 - 7112
(2008/02/03)
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- Sonochemistry: A powerful way of enhancing the efficiency of carbohydrate synthesis
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Using sonication as a means of facilitating organic reactions in carbohydrate chemistry was explored under the conditions used for traditional organic synthesis. An array of representative reactions, including hydroxy group manipulation (acylation, protection/deprotection, acyl group migration), thioglycoside synthesis, azidoglycoside synthesis, 1,3-dipolar cycloaddition and reductive cleavage of benzylidene, commonly used in the synthesis of carbohydrate derivatives was examined. A series of glycosylation reactions that employ thioglycosides, glycosyl trichloroacetimidate, glycosyl bromide and glycosyl acetate as the glycosyl donors was also examined. Our results demonstrate that sonication can significantly shorten the reaction time, enhance the reactivity of reactant and lead to superior yield and excellent stereoselectivity. More importantly, a general protocol of glycosylation may finally be developed. Sonication is compatible to the conditions used for traditional organic synthesis. We believe that sonication can also be applied to other areas of synthetic processes.
- Deng, Shenglou,Gangadharmath, Umesh,Chang, Cheng-Wei Tom
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p. 5179 - 5185
(2007/10/03)
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- Formation of 1,1-α, α-glycosidic bonds by intramolecular aglycone delivery. A convergent synthesis of trehalose
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(Matrix presented) We report a new synthesis of trehalose analogs that involves the use of intramolecular aglycone delivery for stereoselective formation of the 1,1-α,α-glycosidic bond. The glycosylation reaction afforded the desired isomer exclusively and in good yield.
- Pratt, Matthew R.,Leigh, Clifton D.,Bertozzi, Carolyn R.
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p. 3185 - 3188
(2007/10/03)
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- Method for eliminating Staphylococcus aureus, novel microorganism of genus Brachybacterium, and care garment, care sheet or care bedclothes, each being immobilized with microorganism of genus Brachybacterium
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A method for eliminating Staphylococcus aureus is disclosed, including inoculating a microorganism of the genus Brachybacterium to Staphylococcus aureus to eliminate Staphylococcus aureus. A care garment, a care sheet or care bedclothes, each being immobilized with a microorganism or genus Brachybacterium, is also disclosed. One of the microorganismns of the genus Brachybacterium useful in the invention is novel and is deposited as a bacterial strain AAA-a of the genus Brachybacterium (Accession No. FERM BP-6848) in the International Depositary Authority for the deposit of microorganism.
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- Process for producing D-glucuronolactone
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Trehalose is oxidized to give oxidized trehalose which then is hydrolyzed to produce D-glucuronolactone which is thereafter recovered to realize high-yield and low-cost production of D-glucuronolactone.
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- Fermented milk product
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Lactic acid bacteria of the genus Lactobacillus having the following specific properties: (1) an increased amount of acidity of lactic acid when storing a product cultured by the bacteria at 10° C. for two weeks being 0.5% or less; (2) an activity of cell membrane bound adenosine triphosphatase-being 5 μmol.Pi/min/mg protein or less; and (3) the bacteria having neomycin resistance. Furthermore, a fermented milk product containing the lactic acid bacteria is disclosed.
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- Energy-supplementing saccharide source and its uses
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Trehalose, prepared by allowing a non-reducing saccharide-forming enzyme to act on partial starch hydrolysates exhibiting a reducing power and having a degree of polymerization (DP) of 3-25, is advantageously used as an energy-supplementing saccharide source and used in energy-supplementing compositions as an effective ingredient. The saccharide source and compositions can be suitably used as pharmaceutical compositions for supplementing energy for living bodies without fear of causing side effects.
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- Synthesis and glycosylation shift of 1,1'-disaccharides
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Nineteen kinds of nonreducing 1,1'-disaccharides have synthesized by modified Koenigs-Knorr method, and characterized by NMR. The glycosylation shift of each anomeric carbon has been estimated.
- Nishizawa,Kodama,Yamane,Kayano,Hatakeyama,Yamada
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p. 982 - 984
(2007/10/02)
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- Pharmaceutical compositions comprising selected lactobacillus strains
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Topical pharmaceutical compositions, suited for the use in gynecology and urology, comprise as active principles selected Lactobacillus strains isolated from vaginal or urologic habitat of asymptomatic patients.
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- CATALYTIC VERSATILITY OF TREHALASE: SYNTHESIS OF α-D-GLUCOPYRANOSYL α-D-XYLOPYRANOSIDE FROM β-D-GLUCOSYL FLUORIDE AND α-d-XYLOSE
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Trehalase was previously shown (see. ref. 5) to hydrolyze α-D-glucosyl fluoride, forming β-D-glucose, and to synthesize α,α-trehalose from β-D-glucosyl fluoride plus α-D-glucose.Present observations further define the enzyme's separate cosubstrate requirements in utilizing these nonglycosidic substrates. α-D-Glucopyranose and α-D-xylopyranose were found to be uniquely effective in enabling Trichoderma reesei trehalase to catalyze reactions with β-D-glucosyl fluoride.As little as 0.2mM added α-D-glucose (0.4mM α-D-xylose) substantially increased the rate of enzymically catalyzed release of fluoride from 25mM β-D-glucosyl fluoride at 0 deg C.Digests of β-D-glucosyl fluoride plus α-D-xylose yielded the α,α-trehalose analog, α-D-glucopyranosyl α-D-xylopyranoside, as a transient (ie., subsequently hydrolyzed) transfer-product.The need for an aldopyranose acceptor having an axial 1-OH group when β-D-glucosyl fluoride is the donor, and for water when α-D-glucosyl fluoride is the substrate, indicates that the catalytic groups of trehalose have the flexibility to catalyse different stereochemical reactions.
- Kasumi, Takafumi,Brewer, Curtis F.,Reese, Elwyn T.,Hehre, Edward J.
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- Heteropolysaccharide S-139
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The new heteropolysaccharide S-139, prepared by fermentation of an unnamed Psuedomonas species, ATCC 31644 has valuable properties as a thickening, suspending and stabilizing agent in aqueous systems. Polysaccharide S-139 is principally composed of carbohydrate, protein (about 17%), and acyl groups (about 5% calculated as O-acetyl) as the glycosidically linked ester. The carbohydrate portion contains about 14% uronic acid (based on wt. gum) and the neutral sugars rhamnose, mannose, glucose, and galactose in the approximate molar ratio of 2.5:1:1.5:1 respectively.
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- NOUVELLE METHODE DE SYNTHESE STEREOSELECTIVE DE GLYCOSIDES. SYNTHESE DES α,α-TREHALOSE, ANALOGUES galacto, manno ET AUTRES α-D-GLYCOSIDES
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In the presence of trifluoromethanesulfonic (triflic) anhydride as catalyst and dichloromethane as solvent, in the cold, 2,3,4,6-tetra-O-benzyl-D-glucopyranose, 2,3,4,6-tetra-O-benzyl-D-galactopyranose, and 2,3,4,6-tetra-O-benzyl-D-mannopyranose were converted in almost quantitative yield to a 2:1 mixture of the corresponding α,α-(1->1) and α,β-(1->1) disaccharides.Hence, pure 2,3,4,6,2',3',4',6'-octa-O-benzyl derivatives of α,α-trehalose, and the D-galacto and D-manno analogues were obtained, after column chromatography, in 55-65 percent yield.Hydrogenolysis gave the corresponding free sugars.The pure anomers were obtained in 10-34 percent yield.The potentiality of the method was demonstrated by the synthesis of 2,3,4,6-tetra-O-benzyl-α-D-glucopyranosyl 2,3:4,5-di-O-isopropylidene-β-D-fructopyranoside in 50 percent yield, and of N-(benzyloxycarbonyl)-3-O-(2,3,4,6-tetra-O-benzyl-α-D-glucopyranosyl)-L-threonine methyl ester in 65 percent yield.
- Pavia, Andre A.,Rocheville, Jean-Michel,Ung, Sak N.
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