Effects of Polyhydroxy Compounds on Enzymatic Synthesis of L-Tryptophan Catalyzed by Tryptophan Synthase

Xu, Lisheng; Wang, Zhiyuan; Liu, Junzhong; Mao, Pingting; Zhang, Hongjuan; Gao, Ji; Liu, Qian; Jiao, Qingcai

doi:10.1007/s10562-011-0743-7

Cited by 4 publications

(2 citation statements)

References 19 publications

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“…[16][17][18] ZnAl 2 O 4 has been widely used in many fields, such as magnetic storage devices, catalysts, photosynthesis enhancement, high-temperature ceramics, laser and fluorescent substrate materials and sensing and dielectric materials. [19][20][21][22][23][24][25] However, the photocatalytic activity of ZnAl 2 O 4 is affected by the fast recombination speed and the weak reducing capacity of photocarriers due to the relative positive conductance band potential. Therefore, various modification methods have been adopted to overcome the above problems, such as adjusting the facet exposure, ion doping, noble metal loading and heterostructure construction.…”

Section: Introductionmentioning

confidence: 99%

Magnetically Recoverable Cr and Mn Co-Doped Zn0.95−xCr0.05MnxAl2O4 Nanoparticles for Dye Degradation Under Simulated Sunlight Irradiation

Wei

Huang

et al. 2020

Journal of Elec Materi

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Magnetically recyclable Zn 0.95Àx Cr 0.05 Mn x Al 2 O 4 nanoparticles were synthesized via hydrothermal and heat treatment techniques. The crystal structure, morphology, and photoelectrochemical and magnetic properties of the samples were characterized by x-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), x-ray energy-dispersive spectroscopy (XEDS), ultraviolet-visible (UV-Vis) spectroscopy, photoluminescence spectra (PL), vibrating-sample magnetometer (VSM), electrochemical impedance spectra (EIS) and transient photocurrent responses, and the photocatalytic activity of the samples were evaluated by the photodegradation of methyl orange (MO) dye under simulated sunlight irradiation. The experimental results show that Zn 0.95Àx Cr 0.05 Mn x Al 2 O 4 nanoparticles possess a cubic spinel structure without impurity phases. Cr and Mn ions are successfully substituted in the lattice site of Zn 2+ and enter the ZnAl 2 O 4 matrix. The morphology of the samples exhibits irregular spherical or ellipsoid particles with small particle size and good dispersion. The average crystallite size and the bandgap decrease with an increase in Mn ion concentration. Meanwhile, the co-doped samples exhibit obvious room-temperature ferromagnetism, the photoluminescence intensity decreases and a luminescence quenching phenomenon occurs. In addition, Zn 0.95Àx Cr 0.05 Mn x Al 2 O 4 nanoparticles exhibit excellent photocatalytic activity and possess better photocatalytic reusability in degradation of MO aqueous solution.

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Section: Introductionmentioning

confidence: 99%

Magnetically Recoverable Cr and Mn Co-Doped Zn0.95−xCr0.05MnxAl2O4 Nanoparticles for Dye Degradation Under Simulated Sunlight Irradiation

Wei

Huang

et al. 2020

Journal of Elec Materi

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“…(2) Secondly, metals could provoke a decrease in electron-hole recombination rate, acting as electron traps. Therefore, there are some examples in the literature of the doping of titania with metals such as Fe [4,5], Pd [6], Pt [7],Cr [8], rare-earth metals [9]. The present piece of research is aimed at exploring the effect of the presence of iron on the structure and photocatalytic activity of titania-based catalyst.…”

Section: Introductionmentioning

confidence: 99%

Preparation and Photocatalytic Activity of Fe-Doped TiO<sub>2</sub> Nanopowders

Ren

Teng

2009

MSF

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(0-2%) Fe-doped TiO2 nanopowders were prepared by sol-gel method. The Size, structure, appearance, the light absorption and hydroscopicity properties were characterized by XRD, TEM, UV-Vis and FTIR. The photocatalytic degradation of crystal violet under UV over catalyst was used as a probe reaction to evaluate their photocatalytic activity, the dependence of photocatalytic properties on Fe doping content and roasting temperature were also discussed. The results show that the process of phase transfer of TiO2 from anatase to rutile was promoted by doping Fe, 1.5% Fe3+-doped TiO2 nanoparticles formed many defects at grain boundaries, inhibited effectively the recombination of the photoproduced e-/h+, improved the efficiency of photons, enhanced the absorbing water function of catalyst, and 1.5% Fe3+-doped TiO2 revealled strongly absorption in UV and widened obviously absorption in Vis. Photocatalytic degradation ratio of crystal violet (4mg/L) on 1.5% Fe3+-doped TiO2 was increased 30% than pure TiO2.

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Dynamic Kinetic Resolution for Asymmetric Synthesis of L‐Noncanonical Amino Acids from D‐Ser Using Tryptophan Synthase and Alanine Racemase

Gao

et al. 2019

Eur J Org Chem

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L‐Ser is often used to synthesize some significant l‐noncanonical α‐amino acids(l‐ncAAs), which are the prevalent intermediates and precursors for functional synthetic compounds. In this study, threonine aldolase from Escherichia coli k‐12 MG1655 has been used to synthesize l‐Ser. In contrast to the maximum catalytic capacity (20 g/L) for l‐threonine aldolase(LTA), d‐Ser was synthesized with high yield (240 g/L) from cheap Gly and paraformaldehyde using d‐threonine aldolase (DTA) from Arthrobacter sp ATCC. In order to fully utilize d‐Ser and expand the resource of l‐Ser, a dynamic kinetic resolution system was constructed to convert d/dl‐Ser to l‐Ser through combining alanine racemase (Alr) from Bacillus subtilis with l‐tryptophan synthase (TrpS) from Escherichia coli k‐12 MG1655, and l‐ncAAs including l‐Trp and l‐Cys derivatives were synthesized with excellent enantioselectivity and in high yields. The results indicated l‐ncAAs could be efficiently synthesized from d‐Ser using this original and green dynamic kinetic resolution system, and the reliable l‐Ser resource has been established from simple and achiral substrates.

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Effects of Polyhydroxy Compounds on Enzymatic Synthesis of L-Tryptophan Catalyzed by Tryptophan Synthase

Cited by 4 publications

References 19 publications

Magnetically Recoverable Cr and Mn Co-Doped Zn0.95−xCr0.05MnxAl2O4 Nanoparticles for Dye Degradation Under Simulated Sunlight Irradiation

Magnetically Recoverable Cr and Mn Co-Doped Zn0.95−xCr0.05MnxAl2O4 Nanoparticles for Dye Degradation Under Simulated Sunlight Irradiation

Preparation and Photocatalytic Activity of Fe-Doped TiO<sub>2</sub> Nanopowders

Dynamic Kinetic Resolution for Asymmetric Synthesis of L‐Noncanonical Amino Acids from D‐Ser Using Tryptophan Synthase and Alanine Racemase

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