Aim An industrial enzyme β-glucanase was used to transfortn notoginsenoside Fe for the first time. Methods Notoginsenoside Fe was isolated from the leave saponin of Panax notoginseng （Burk.） Chen FH. The enzymatica...Aim An industrial enzyme β-glucanase was used to transfortn notoginsenoside Fe for the first time. Methods Notoginsenoside Fe was isolated from the leave saponin of Panax notoginseng （Burk.） Chen FH. The enzymatically transformed compounds were detected by HPLC and two transformed compounds were identified as 20 （S） -protopanaxadiol-20- O- α-L-arabinofuranosyl （ 1→6 ） - β-gluco- pyranoside, ginsenoside-Mc） and 20（S）-protopanaxadiol-20-O-β-D-glucopyranoside compound-K （C-K） respectively on the basis of their ^1H NMR and ^13 C NMR spectral data. Results Based on the enzymolytic kinetic curve, the transformation rate of notoginsenoside Fe reached 95% after 24 h. Conclusion The enzymatic transformation pathway of notoginsenoside Fe by β-glucanase has been proposed as notoginsenoside Fe→ginsenoside Mc→C-K.展开更多
A block copolymer of 2-dimethylaminoethyl methacrylate(DMAEMA) and glycidyl methacrylate(GMA)was grafted onto the surface of magnetic nanoparticles(Fe3O4) via atom transfer radical polymerization.The resultant PGMA-b-...A block copolymer of 2-dimethylaminoethyl methacrylate(DMAEMA) and glycidyl methacrylate(GMA)was grafted onto the surface of magnetic nanoparticles(Fe3O4) via atom transfer radical polymerization.The resultant PGMA-b-PDMAEMA-grafted-Fe3O4 magnetic nanoparticles with amino and epoxy groups were characterized by Fourier transform infrared spectroscopy, powder X-ray diffraction, thermo-gravimetric analysis, and scanning electron microscopy. Lipase from Burkholderia cepacia was successfully immobilized onto the magnetic nanoparticles by physical adsorption and covalent bonding. The immobilization capacity of the magnetic particles is 0.5 mg lipase per mg support, with an activity recovery of up to 43.1% under the optimum immobilization condition. Biochemical characterization shows that the immobilized lipase exhibits improved thermal stability, good tolerance to organic solvents with high lg P, and higher p H stability than the free lipase at p H 9.0. After six consecutive cycles, the residual activity of the immobilized lipase is still over55% of its initial activity.展开更多
Fe(Ⅱ)/α-ketoglutarate(αKG)-dependent oxygenases catalyze the oxidative modification of various molecules,from DNA,RNA,and proteins to primary and secondary metabolites.They also catalyze a variety of biochemical re...Fe(Ⅱ)/α-ketoglutarate(αKG)-dependent oxygenases catalyze the oxidative modification of various molecules,from DNA,RNA,and proteins to primary and secondary metabolites.They also catalyze a variety of biochemical reactions,including hydroxylation,halogenation,desaturation,epoxidation,cyclization,peroxidation,epimeriza-tion,and rearrangement.Given the versatile catalytic capability of such oxygenases,numerous studies have been conducted to characterize their functions and elucidate their structure-function relationships over the past few decades.Amino acids,particularly nonproteinogenic amino acids,are considered as important building blocks for chemical synthesis and components for natural product biosynthesis.In addition,the Fe(Ⅱ)/αKG-dependent oxy-genase superfamily includes important enzymes for generating amino acid derivatives,as they efficiently modify various free-standing amino acids.The recent discovery of new Fe(Ⅱ)/αKG-dependent oxygenases and the repur-posing of known enzymes in this superfamily have promoted the generation of useful amino acid derivatives.Therefore,this study will focus on the recent progress achieved from 2019 to 2022 to provide a clear view of the mechanism by which these enzymes have expanded the repertoire of free amino acid oxidative modifications.展开更多
文摘Aim An industrial enzyme β-glucanase was used to transfortn notoginsenoside Fe for the first time. Methods Notoginsenoside Fe was isolated from the leave saponin of Panax notoginseng （Burk.） Chen FH. The enzymatically transformed compounds were detected by HPLC and two transformed compounds were identified as 20 （S） -protopanaxadiol-20- O- α-L-arabinofuranosyl （ 1→6 ） - β-gluco- pyranoside, ginsenoside-Mc） and 20（S）-protopanaxadiol-20-O-β-D-glucopyranoside compound-K （C-K） respectively on the basis of their ^1H NMR and ^13 C NMR spectral data. Results Based on the enzymolytic kinetic curve, the transformation rate of notoginsenoside Fe reached 95% after 24 h. Conclusion The enzymatic transformation pathway of notoginsenoside Fe by β-glucanase has been proposed as notoginsenoside Fe→ginsenoside Mc→C-K.
基金Supported by the National Basic Research Program of China(2009CB724706)
文摘A block copolymer of 2-dimethylaminoethyl methacrylate(DMAEMA) and glycidyl methacrylate(GMA)was grafted onto the surface of magnetic nanoparticles(Fe3O4) via atom transfer radical polymerization.The resultant PGMA-b-PDMAEMA-grafted-Fe3O4 magnetic nanoparticles with amino and epoxy groups were characterized by Fourier transform infrared spectroscopy, powder X-ray diffraction, thermo-gravimetric analysis, and scanning electron microscopy. Lipase from Burkholderia cepacia was successfully immobilized onto the magnetic nanoparticles by physical adsorption and covalent bonding. The immobilization capacity of the magnetic particles is 0.5 mg lipase per mg support, with an activity recovery of up to 43.1% under the optimum immobilization condition. Biochemical characterization shows that the immobilized lipase exhibits improved thermal stability, good tolerance to organic solvents with high lg P, and higher p H stability than the free lipase at p H 9.0. After six consecutive cycles, the residual activity of the immobilized lipase is still over55% of its initial activity.
基金supported in part by a Grant-in-Aid for Scientific Research from the Ministry of Education,Culture,Sports,Science and Technology,Japan(JSPS KAKENHI Grant No.JP16H06443,JP20KK013,and JP20H00490)Japan Science and Technology Agency(JST SICORP Grant No.JPMJSC1701)+2 种基金the New Energy and Industrial Technology Development Organization(NEDO,Grant No.JPNP20011)Japan Agency for Medical Research and Development(AMED)(Grant No.JP21ak0101164)H.T.is a recipient of the JSPS Postdoctoral Fellowship for Foreign Researchers(ID No.P18404).
文摘Fe(Ⅱ)/α-ketoglutarate(αKG)-dependent oxygenases catalyze the oxidative modification of various molecules,from DNA,RNA,and proteins to primary and secondary metabolites.They also catalyze a variety of biochemical reactions,including hydroxylation,halogenation,desaturation,epoxidation,cyclization,peroxidation,epimeriza-tion,and rearrangement.Given the versatile catalytic capability of such oxygenases,numerous studies have been conducted to characterize their functions and elucidate their structure-function relationships over the past few decades.Amino acids,particularly nonproteinogenic amino acids,are considered as important building blocks for chemical synthesis and components for natural product biosynthesis.In addition,the Fe(Ⅱ)/αKG-dependent oxy-genase superfamily includes important enzymes for generating amino acid derivatives,as they efficiently modify various free-standing amino acids.The recent discovery of new Fe(Ⅱ)/αKG-dependent oxygenases and the repur-posing of known enzymes in this superfamily have promoted the generation of useful amino acid derivatives.Therefore,this study will focus on the recent progress achieved from 2019 to 2022 to provide a clear view of the mechanism by which these enzymes have expanded the repertoire of free amino acid oxidative modifications.
