- Enzymatic synthesis of propyl-α-glycosides and their application as emulsifying and antibacterial agents
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Alkyl glycosides have been effectively used in many industries because of their biodegradable, emulsification and antibacterial properties. In this study, the alkyl glycoside of propyl glycosides (PGn) was synthesized using β-cyclodextrin (β-CD) and 1-propanol through the transglycosylation reaction of recombinant cyclodextrin glycosyltransferase (CGTase) from the Bacillus circulans A11. The optimal condition for the synthesis of propyl glycosides consisted of an incubation of 1.5% (w/v) β-CD and 500 U/mL of CGTase in a water/propanol content containing 10% (v/v) 1-propanol at pH 6.0, 50°C for 96 h. Upon analysis of the product at the optimal condition by TLC, at least three products which move faster than glucose were observed. These transferred products were formed with molecular weights of 222.1, 384.1 and 546.4 daltons as determined by mass spectrometry analysis; these values were in accordance with propyl glucoside (PG1), propyl maltoside (PG2) and propyl maltotrioside (PG3), respectively. PG1 and PG2 were produced and prepared on a large scale and subsequently purified by preparative TLC. The combined 1H- and 13C-NMR analysis confirmed that the structures of PG1 and PG2 were propyl-α-D-glucopyranoside and propyl-α-D-maltopyranoside, respectively. Both PG1 and PG2 showed emulsification activity and stability in their formation in water and n-hexadecane. Furthermore, the antibacterial activity of both products was determined and it was found that PG2 had a higher antibacterial activity against Staphylococcus aureus and Escherichia coli than that of PG1.
- Charoensapyanan, Rittichai,Ito, Kazuo,Rudeekulthamrong, Prakarn,Kaulpiboon, Jarunee
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p. 389 - 401
(2016/07/30)
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- Purification, characterization, and gene identification of an α-glucosyl transfer enzyme, a novel type α-glucosidase from Xanthomonas campestris WU-9701
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The α-glucosyl transfer enzyme (XgtA), a novel type α-glucosidase produced by Xanthomonas campestris WU-9701, was purified from the cell-free extract and characterized. The molecular weight of XgtA is estimated to be 57 kDa by SDS-PAGE and 60 kDa by gel filtration, indicating that XgtA is a monomeric enzyme. Kinetic properties of XgtA were determined for α-glucosyl transfer and maltose-hydrolyzing activities using maltose as the α-glucosyl donor, and if necessary, hydroquinone as the acceptor. The Vmax value for α-glucosyl transfer activity was 1.3 × 10-2 (mM/s); this value was 3.9-fold as much as that for maltose-hydrolyzing activity. XgtA neither produced maltooligosaccharides nor hydrolyzed sucrose. The gene encoding XgtA that contained a 1614-bp open reading frame was cloned, identified, and highly expressed in Escherichia coli JM109 as the host. Site-directed mutagenesis identified Asp201, Glu270, and Asp331 as the catalytic sites of XgtA, indicating that XgtA belongs to the glycoside hydrolase family 13.
- Sato, Toshiyuki,Hasegawa, Nobukazu,Saito, Jun,Umezawa, Satoru,Honda, Yuki,Kino, Kuniki,Kirimura, Kohtaro
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body text
p. 20 - 27
(2012/09/05)
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- Isolation and characterization of a novel α-glucosidase with transglycosylation activity from Arthrobacter sp. DL001
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A strain of Arthrobacter sp. DL001 with high transglycosylation activity was successfully isolated from the Yellow Sea of China. To purify the extracellular enzyme responsible for transglycosylation, a four-step protocol was adopted and the enzyme with electrophoretical purity was obtained. The purified enzyme has a molecular mass of 210 kDa and displays a narrow hydrolysis specificity towards α-1,4-glucosidic bond. Its hydrolytic activity was identified as decreasing in the order of maltotriose > panose > maltose. Only 3.61% maltose activity occurs when p-nitrophenyl α-d-glycopyranoside serves as a substrate, suggesting that this enzyme belongs to the type II α-glucosidase. In addition, the enzyme was able to transfer glucosyl groups from the donors containing α-1,4-glucosidic bond specific to glucosides, xylosides and alkyl alcohols in α-1,4- or α-1,6-manners. A decreased order of activity was observed when maltose, maltotriose, panose, β-cyclodextrin and soluble starch served as glycosyl donors, respectively. When maltose was utilized as a donor and a series of p-nitrophenyl-glycosides as acceptors, the glucosidase was capable of transferring glucosyl groups to p-nitrophenyl-glucosides and p-nitrophenyl-xylosides in α-1,4- or α-1,6-manners. The yields of p-nitrophenyl-oligosaccharides could reach 42-60% in 2 h. When a series of alkyl alcohols were utilized as acceptors, the enzyme exhibited its transglycosylation activities not only to the primary alcohols but also to the secondary alcohols with carbon chain length 1-4. Therefore, all the results indicated that the purified α-glucosidase present a useful tool for the biosynthesis of oligosaccharides and alkyl glucosides.
- Zhou, Kun,Luan, Hong-Wei,Hu, Ying,Ge, Guang-Bo,Liu, Xing-Bao,Ma, Xiao-Chi,Hou, Jie,Wang, Xiu-Li,Yang, Ling
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experimental part
p. 48 - 57
(2012/09/07)
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- Significantly Improved Equilibrium Yield of Long-Chain Alkyl Glucosides via Reverse Hydrolysis in a Water-Poor System Using Cross-Linked Almond Meal as a Cheap and Robust Biocatalyst
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An array of ten β-D-glucopyranosides with varied alkyl chain lengths were enzymatically synthesized. It was found that for longer alkyl chains a lower initial rate and final yield of glucoside was obtained except for methyl glucoside because of the severe toxicity of methanol to the enzyme. From a thermodynamics point of view, the equilibrium constant and Gibbs free energy variation of the glucoside syntheses were systematically investigated. To improve the final yields of the glucosides containing long alkyl chains the equilibrium of the enzymatic glucoside synthesis was altered. The equilibrium yield of decyl β-D-glucoside increased from 1.9% to 6.1% when the water content was reduced from 10% to 5% (v/v) using tert-butanol as a cosolvent and 0.10 mol/L of glucose as a substrate. As for the other longer alkyl chain glucosides, heptyl β-D-glucoside was found to have significant surface activity as well.
- Wang, Qinqqin,Yu, Huilei,Zhao, Na,Li, Chunxiu,Shang, Yazhuo,Liu, Honglai,Xu, Jianhe
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p. 275 - 280
(2016/04/10)
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- Significantly improved equilibrium yield of long-chain alkyl glucosides via reverse hydrolysis in a water-poor system using cross-linked almond meal as a cheap and robust biocatalyst
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An array of ten β-D-glucopyranosides with varied alkyl chain lengths were enzymatically synthesized. It was found that for longer alkyl chains a lower initial rate and final yield of glucoside was obtained except for methyl glucoside because of the severe toxicity of methanol to the enzyme. From a thermodynamics point of view, the equilibrium constant and Gibbs free energy variation of the glucoside syntheses were systematically investigated. To improve the final yields of the glucosides containing long alkyl chains the equilibrium of the enzymatic glucoside synthesis was altered. The equilibrium yield of decyl β-D-glucoside increased from 1.9 to 6.1 when the water content was reduced from 10 to 5 (v/v) using tert-butanol as a cosolvent and 0.10 mol/L of glucose as a substrate. As for the other longer alkyl chain glucosides, heptyl β-D-glucoside was found to have significant surface activity as well.
- Wang, Qinqqin,Yu, Huilei,Zhao, Na,Li, Chunxiu,Shang, Yazhuo,Liu, Honglai,Xu, Jianhe
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p. 275 - 280
(2012/06/29)
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- POLYMER STABILIZER
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A polymer stabilizer comprising the following alkoxy compound: the alkoxy compound: a compound obtained by alkoxylating at least one hydroxyl group contained in a compound of the following formula (1) containing one formyl group or carbonyl group and (n?1) hydroxyl groups in the molecule with an alkyl group having 1 to 12 carbon atoms: [in-line-formulae]CnH2nOn??(1)[/in-line-formulae] (wherein, n represents an integer of 3 or more).
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- A new method of synthesis of alkyl β-glycosides using sucrose as sugar donor
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Cellobiose phosphorylase from Clostridium thermocellum catalyzed the β-anomer-selective synthesis of alkyl glucosides from cellobiose. Synthesis of alkyl β-glucoside from inexpensive sucrose using cellobiose phosphorylase and sucrose phosphorylase from Pseudomonas saccharophilia was investigated. By combined use of these two phosphorylases, alkyl β-glucoside was anomer-selectively synthesized from sucrose and alkyl alcohol.
- Kino, Kuniki,Satake, Ryoko,Morimatsu, Takayuki,Kuratsu, Shoko,Shimizu, Yu,Sato, Masaru,Kirimura, Kohtaro
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p. 2415 - 2417
(2008/12/23)
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