2001-96-9Relevant academic research and scientific papers
Positional specifity of acetylxylan esterases on natural polysaccharide: An NMR study
Uhliariková, Iveta,Vr?anská, Mária,McCleary, Barry V.,Biely, Peter
, p. 3365 - 3372 (2013)
Background Microbial degradation of acetylated plant hemicelluloses involves besides enzymes cleaving the glycosidic linkages also deacetylating enzymes. A detailed knowledge of the mode of action of these enzymes is important in view of the development of efficient bioconversion of plant materials that did not undergo alkaline pretreatment leading to hydrolysis of ester linkages. Methods In this work deacetylation of hardwood acetylglucuronoxylan by acetylxylan esterases from Streptomyces lividans (carbohydrate esterase family 4) and Orpinomyces sp. (carbohydrate esterase family 6) was monitored by 1H-NMR spectroscopy. Results The 1H-NMR resonances of all acetyl groups in the polysaccharide were fully assigned. The targets of both enzymes are 2- and 3-monoacetylated xylopyranosyl residues and, in the case of the Orpinomyces sp. enzyme, also the 2,3-di-O-acetylated xylopyranosyl residues. Both enzymes do not recognize as a substrate the 3-O-acetyl group on xylopyranosyl residues α-1,2-substituted with 4-O-methyl-d-glucuronic acid. Conclusions The 1H-NMR spectroscopy approach to study positional and substrate specificity of AcXEs outlined in this work appears to be a simple way to characterize catalytic properties of enzymes belonging to various CE families. Significance The results contribute to development of efficient and environmentally friendly procedures for enzymatic degradation of plant biomass.
Propargyl-containing xylose and synthesis method thereof
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Paragraph 0036; 0040, (2020/07/28)
The invention discloses propargyl-containing xylose and a preparation method thereof. The method comprises the following steps: using D-xylose as a raw material, carrying out full acetyl protection onthe D-xylose, introducing p-nitrophenoxy into a first position of an obtained compound, and removing acetyl to obtain a compound A; introducing tert-butyl dimethyl into the position 2, the position 3or the position 4 of the obtained compound A to obtain a compound B, a compound C and a compound D, and separating the compound B, the compound C and the compound D; and respectively carrying out acetyl protection on hydroxyl groups of the compound B, the compound C and the compound D, then removing the tert-butyl dimethyl, and respectively introducing propargyl into the position 2, the position3 and the position 4 to obtain the propargyl-containing xylose. According to the method disclosed by the invention, the propargyl is selectively connected to xylose for the first time by using a method for carrying out occupying by using tert-butyl dimethyl (TBS), so that a platform is provided for subsequent connection of the xylose to protein or amino acid, and a foundation is laid for biological research in the future.
Direct Synthesis of para-Nitrophenyl Glycosides from Reducing Sugars in Water
Fairbanks, Antony J.,Qiu, Xin
supporting information, (2020/03/24)
Reducing sugars may be directly converted into the corresponding para-nitrophenyl (pNP) glycosides using 2-chloro-1,3-dimethylimidazolinium chloride (DMC), para-nitrophenol, and a suitable base in aqueous solution. The reaction is stereoselective for sugars with either a hydroxyl or an acetamido group at position 2, yielding the 1,2-trans pNP glycosides. A judicious choice of base allows extension to di-and oligosaccharide substrates, including a complex N-glycan oligosaccharide isolated from natural sources, without the requirement of any protecting group manipulations
Positional specificity of Flavobacterium johnsoniae acetylxylan esterase and acetyl group migration on xylan main chain
Puchart, Vladimír,Gjermansen, Morten,Mastihubová, Mária,M?rkeberg Krogh, Kristian B.R.,Biely, Peter
, (2020/01/09)
A new Flavovacterium johnsoniae isolate encodes an enzyme that is essentially identical with a recently discovered novel acetylxylan esterase, capable of liberating 3-O-acetyl group from 4-O-methyl-D-glucuronic acid-substituted xylopyranosyl (Xylp) residues (Razeq et al., 2018). In addition to deesterification of the 2-O-MeGlcA-substituted Xylp residues in acetylglucuronoxylan, the enzyme acts equally well on doubly acetylated Xylp residues from which it liberates only the 3-O-acetyl groups, leaving the 2-O-acetyl groups untouched. 3-O-Monoacetylated Xylp residues are attacked with a significantly reduced affinity. The resulting 2-O-acetylated xylan was used to investigate for the first time the migration of the 2-O-acetyl group to position 3 within the polysaccharide. In contrast to easy acetyl group migration along the monomeric xylopyranosides or non-reducing-end terminal Xylp residues of xylooligosaccharides, such a migration in the polymer required much longer heating at 100 °C. The specificity of the xylan 3-O-deacetylase was, however, no so strict on acetylated methyl and 4-nitrophenyl xylopyranosides.
The application of aryl substituted derivatives of xylose as environmentally friendly multipurpose pesticides
Belakhov,Garabadzhiu
, p. 3002 - 3007 (2017/07/07)
A series of aryl substituted derivatives of xylose have been synthesized. Biological tests have revealed high fungicidal activity of the resulting compounds against various phythopathogenic fungi. Additional biological studies have demonstrated high plant growth regulatory activity of the compounds synthesized.
Glycosynthase with broad substrate specificity-an efficient biocatalyst for the construction of oligosaccharide library
Wei, Jinhua,Lv, Xun,Lue, Yang,Yang, Gangzhu,Fu, Lifeng,Yang, Liu,Wang, Jianjun,Gao, Jianhui,Cheng, Shuihong,Duan, Qian,Jin, Cheng,Li, Xuebing
supporting information, p. 2414 - 2419 (2013/05/23)
A versatile glycosynthase (TnG-E338A) with strikingly broad substrate scope has been developed from Thermus nonproteolyticus β-glycosidase (TnG) by using site-directed mutagenesis. The practical utility of this biocatalyst has been demonstrated by the facile generation of a small library containing various oligosaccharides and a steroidal glycoside (total 25 compounds) in up to 100 % isolated yield. Moreover, an array of eight gluco-oligosaccharides has been readily synthesized by the enzyme in a one-pot, parallel reaction, which highlights its potential in the combinatorial construction of a carbohydrate library that will assist glycomic and glycotherapeutic research. Significantly, the enzyme provides a means by which glycosynthase technology may be extended to combinatorial chemistry.
Preparation of regioselectively feruloylated p-nitrophenyl α-l-arabinofuranosides and β-d-xylopyranosides-convenient substrates for study of feruloyl esterase specificity
Mastihubova, Maria,Biely, Peter
experimental part, p. 1094 - 1098 (2010/09/12)
p-Nitrophenyl α-l-arabinofuranoside and β-d-xylopyranoside mono-O-ferulates were prepared by 4-O-acetylferuloylation of corresponding enzymatically prepared di-O-acetates followed by deacetylation. An alternative mild acylation catalysed by zinc oxide was tested on xylopyranoside derivatives. The chemoselective methanolysis of the acetyl groups using neutral catalyst dibutyltin oxide at reflux was used as deacetylation method. Under these conditions a significant feruloyl migration was observed mainly on p-nitrophenyl 3-O-feruloyl-β-d-xylopyranoside resulting in low yields of the positional isomers. Investigation of substrate and positional specificity of different types of feruloyl esterases on the presented compounds in enzyme-coupled assays was reported previously.
Carbohydrate-carbohydrate interactions in water with glycophanes as model systems
Morales, Juan Carlos,Zurita, Dacil,Penades, Soledad
, p. 9212 - 9222 (2007/10/03)
The synthesis and conformational properties of glycophanes 2 and 3 (cyclodextrin-cyclophane hybrid receptors containing two maltose units linked by (4-hydroxymethyl) benzoic acid spacer) are described. The binding properties in water of these receptors with a series of 4-nitrophenyl glycosides with α- and β-configurations at the anomeric center have been studied using 1H NMR spectroscopy and molecular mechanics calculations. A comparison of these properties with those of glycophane 1 (an α,α-trehalose containing glycophane) and α-cyclodextrin (αCD) using the same glycosides shows the existence of a stabilizing contribution to the free energy of binding in the case of of glycophanes but not in the case of the αCD system. This contribution is due to carbohydrate-carbohydrate interactions between both host and guest lipophilic sugar surfaces. Glycophanes 1, 2, and 3 show similar α/β selectivity on binding the ligands, despite the great flexibility of 3 related to 1 and 2. Parallels are drawn between the thermodynamic behavior of these model systems and that proposed for sugar- protein interactions.
Synthesis of 2- and 4-nitrophenyl β-glycosides of β-(1 → 4)-D-xylo-oligosaccharides of dp 2-4
Takeo,Ohguchi,Hasegawa,Kitamura
, p. 231 - 244 (2007/10/03)
2- and 4-Nitrophenyl β-D-xylopyranosides (4 and 5) were transformed, via dibutyltin oxide-mediated acylation, into the corresponding 2,3-di-O-benzoyl derivatives 11 and 15. Xylobiose and xylotriose were easily isolated by charcoal column chromatography from a commercially available material and converted into the di- and trisaccharide methyl 1-thio-β-glycosides 36 and 37. The 2- and 4-nitrophenyl β-glycosides of the β-(1 → 4)-D-xylo-oligosaccharides of dp 2-4 were synthesized by N-iodosuccinimide-silver triflate-promoted condensation using 11 and 15 as the glycosyl acceptors and ethyl 1-thio-β-D-xylopyranoside triacetate 16, 36, and 37 as the glycosyl donors. Also described are an improved preparation of 4 and 5, and the synthesis of 1-naphthyl β-D-xylopyranoside, as well as an alternative approach to the 2- and 4-nitrophenyl β-xylobiosides.
A stereoselective O-aryl glycosylation procedure via 1,2-cyclic sulfite
El Arabi Aouad, Mohammed,El Meslouti, Ahmed,Uzan, Raoul,Beaupere, Daniel
, p. 6279 - 6282 (2007/10/02)
In a one-pot procedure, treatment of partially protected D-glucose and unprotected D-xylose, with N,N'-thionyldiimidazole and then phenoxide ions give stereoselectively β-O-aryl glycosides.
