- Efficient chemoenzymatic synthesis of novel galacto-N-biose derivatives and their sialylated forms
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Galacto-N-biose (GNB) derivatives were efficiently synthesized from galactose derivatives via a one-pot two-enzyme system containing two promiscuous enzymes from Bifidobacterium infantis: a galactokinase (BiGalK) and a d-galactosyl-β1-3-N-acetyl-d-hexosamine phosphorylase (BiGalHexNAcP). Mono-sialyl and di-sialyl galacto-N-biose derivatives were then prepared using a one-pot two-enzyme system containing a CMP-sialic acid synthetase and an α2-3-sialyltransferase or an α2-6-sialyltransferase.
- Li, Lei,Liu, Yonghui,Li, Tiehai,Wang, Wenjun,Yu, Zaikuan,Ma, Cheng,Qu, Jingyao,Zhao, Wei,Chen, Xi,Wang, Peng G.
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- A highly efficient galactokinase from Bifidobacterium infantis with broad substrate specificity
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Galactokinase (GalK), particularly GalK from Escherichia coli, has been widely employed for the synthesis of sugar-1-phosphates. In this study, a GalK from Bifidobacterium infantis ATCC 15697 (BiGalK) was cloned and over-expressed with a yield of over 80 mg/L cell cultures. The kcat/Km value of recombinant BiGalK toward galactose (164 s-1 mM -1) is 296 times higher than that of GalK from E. coli, indicating that BiGalK is much more efficient in the phosphorylation of galactose. The enzyme also exhibits activity toward galacturonic acid, which has never been observed on other wild type GalKs. Further activity assays showed that BiGalK has broad substrate specificity toward both sugars and phosphate donors. These features make BiGalK an attractive candidate for the large scale preparation of galactose-1-phosphate and derivatives.
- Li, Lei,Liu, Yonghui,Wang, Wenjun,Cheng, Jiansong,Zhao, Wei,Wang, Peng
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experimental part
p. 35 - 39
(2012/08/08)
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- Studies on the substrate specificity of Escherichia coli galactokinase
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(Martix presented) In vitro glycorandomization (IVG) technology is dependent upon the ability to rapidly synthesize sugar phosphates. Compared with chemical synthesis, enzymatic (kinase) routes to sugar phosphates would be attractive for this application. This work focuses upon the development of a high-throughput colorimetric galactokinase (GalK) assay and its application toward probing the substrate specificity and kinetic parameters of Escherichia coli GalK. The demonstrated dinitrosalicylic assay should also be generally applicable to a variety of sugar-processing enzymes.
- Yang, Jie,Fu, Xun,Jia, Qiang,Shen, Jie,Biggins, John B.,Jiang, Jiqing,Zhao, Jingjing,Schmidt, Joshua J.,Wang, Peng G.,Thorson, Jon S.
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p. 2223 - 2226
(2007/10/03)
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- Synthesis of uridine 5′(α-D-fucopyranosyl diphosphate) and (digitoxigenin-3β-yl)-β-D-fucopyranoside and enzymatic β-D-fucosylation of cardenolide aglycones in Digitalis lanata
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The phosphorylation of 2,3,4-tri-Oacetyl-α-D-fucopyranose with o-phenylene phosphochloridate yielded α-D-fucopyranosyl phosphate which was used for condensation with undine 5′-monophosphomorpholidate to give uridine 5′-(α-D-fucopyranosyl diphosphate) (UDP-α-D-fucose). A crude enzyme preparation from young leaves of Digitalis lanata EHRH has been shown to catalyze the transfer of D-fucose from synthetic UDP-α-D-fucose to cardenolide aglycones, such as digitoxigenin. The reaction product was identified and characterized by chemical synthesis, HPLC, and spectral methods as the 3 β-O-β-D-fucopyranoside of digitoxigenin (digiproside). Copyright
- Faust,Theurer,Eger,Kreis
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p. 140 - 149
(2007/10/02)
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