ADVANCED SYNTHESIS & CATALYSIS
·
2018
·Vol. 361
·期 3
·556-561
·
IF 5.123
Peiyuan Yao,Zefei Xu,Shanshan Yu,Qiaqing Wu,Dunming Zhu
The morphinan skeleton is an important sub-structure in many medicines such as dextromethorphan, and can be constructed from 1-benzyl-1,2,3,4,5,6,7,8-octahydroisoquinoline (1-benzyl-OHIQ) derivatives. 1-Benzyl-3,4,5,6,7,8-hexahydroisoquinolines (1-benzyl-HHIQs), the precursors of 1-benzyl-OHIQs, constitute a type of bulky α, β-unsaturated imines. Until now, the application of imine reductases (IREDs) to α, β-unsaturated imines has only rarely been reported. In this study, through evaluation of 48 IREDs, both enantiomers of 1-(4-methoxybenzyl)-1,2,3,4,5,6,7,8-octahydroisoquinoline (1-(4-methoxybenzyl)-OHIQ) were obtained in high yield and excellent optical purity. Among the enzymes, the most steric hindrance-tolerant IRED from Sandarearacinus amylolyticus (IR40) was able to convert various phenyl substituted 1-benzyl-HHIQ to the corresponding 1-benzyl-OHIQ derivatives with excellent enantiometric excess. These results provide an effective route to synthesize these important compounds via enantioselective reduction of bulky α, β-unsaturated imine precursors, which can be readily prepared from 2-(1-cyclohexenyl)ethylamine and corresponding aryl acetic acids.
✓ 已验证
DOI
高影响因子
ANALYTICAL AND BIOANALYTICAL CHEMISTRY
·
2023
·Vol. 415
·期 9
·1733-1740
·
IF 4.3
Tang Kexin,Dong Jiacheng,Zheng Zhengheng,Zhang Ting,Pan Huayi,Jia Honghua,Li Yan,Wei Ping
ω-Transaminases (ω-TAs) are widely available for the production of chiral amines and unnatural amino acids. Herein, a rapid spectrophotometric method was developed for screening ω-TAs based on the colored products that can be generated from transamination reactions between aliphatic α-diketones and amino donors catalyzed by ω-TAs. The possible mechanism of the formation of the colored product was investigated according to LC-Q-TOF–MS analysis. Among seven diketones, 2,3-butanedione was selected as the most suitable amino acceptor for colorimetric screening of ω-TAs with high efficiency, high sensitivity, and low background interference. Meanwhile, the absorbance of the colored product generated by 2,3-butanedione catalyzed by ω-TAs in this method was linearly correlated with the results by HPLC analysis. This method was also confirmed to effectively screen ω-TA mutants with high activity towards isopropylamine. Graphical Abstract
✓ 已验证
DOI
PubMed
高影响因子
PROCESS BIOCHEMISTRY
·
2021
·
IF 3.757
Huabiao Miao,Rui Jiang,Nanyu Han,Yu Ma,Qian Wu,Yuelin Mu,Zunxi Huang
Amylases have been widely applied for starch saccharification in the food, paper, pharmaceutical, and textile industries. In the present study, α-amylase DL-3-4−1 from B. amyloliquefaciens was successfully expressed in B. subtilis. The enzymatic activity exhibited high stability in a pH range from 4.0 to 11.0 and moderate thermostability. Furthermore, excellent stability was observed when incubated with metal ions, detergents, inhibitors, and organic solvents. Resistance against ethanol, urea, and guanidine−HCl was also observed. More importantly, a strategy to enhance the extracellular expression of α-amylase DL-3-4−1 was developed using 173 Sec-type signal peptides (SPs) as a library based on a fast and sequence-independent method. Fourteen SPs were identified with significantly increased yields of DL-3-4−1 via a high-throughput assay. Specifically, the enzymatic activity of the α-amylase-producing strain containing the signal peptide SP5D10 (YomL) was 3.74-fold higher than that of the strain with the wild type signal peptide (87.30 U/OD). In brief, the maximum specific activity of an α-amylase-producing strain containing the YomL signal peptide was 326.45 U/OD. This is the first report of an α-amylase that exhibits ethanol, urea, and guanidine−HCl tolerance. Hence, this α-amylase represents a promising candidate for future use in industry.
✓ 已验证
DOI
高影响因子
SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
·
2021
·
IF 4.098
Xiaogang He,Xiang Han,Jiaping Yu,Yulong Feng,Ganghui Chu
α- Glucosidase is one of the main enzymes causing elevated blood glucose, and Coreopsis tinctoria extract can be used as a natural inhibitor of α -Glucosidase. Therefore, a new method was proposed for predicting the inhibitory activity on α- Glucosidase of Coreopsis tinctoria extract based on near infrared spectroscopy. The absorbance of the inhibitory system was measured by ultraviolet spectroscopy, which was used to study the inhibitory activity on a-glucosidase of Coreopsis tinctoria extract. The near infrared spectra of the solid samples were collected. By selecting spectral preprocessing and optimizing spectral bands, a rapid prediction model of the inhibitory activity was established by partial least squares regression. The root mean square error of cross-validation (RMSECV), correlation coefficient (R) value and the ratio of prediction to deviation (RPD) value were used as indicators of the evaluation model. The near infrared spectrum model was established by combining the best spectral preprocessing of the continuous wavelet transform (CWT) and the best spectral band. The root mean square error of cross-validation (RMSECV) of this model was 0.815%, the correlation coefficient (R) value was 0.942, and the ratio of prediction to deviation (RPD) was 3.0. The root mean square error of prediction (RMSEP) of the model by prediction set was 0.819%, the correlation coefficient (R) value was 0.950, and the RPD was 3.2. The model shows that the fitting relationship between the predicted inhibition value and the reference inhibition value of the near infrared spectral model is good. The results showed that there was a good correlation between near infrared spectroscopy and the inhibitory activity of Coreopsis tinctoria extract. Thus, the established model was robust and effective and could be used for rapid quantification of α -Glucosidase inhibitory activity. The prediction method is simple and rapid, and can be extended to study the inhibition of other medicinal plants.
✓ 已验证
DOI
PubMed
高影响因子
ZEITSCHRIFT FUR NATURFORSCHUNG SECTION A-A JOURNAL OF PHYSICAL SCIENCES
·
2021
·Vol. 77
·期 3
·269-278
·
IF 1.426
Zizheng Yue,Wenlin Feng
In this work, a fiber-optic fluoride-ion-detection Michelson interferometer based on the thin-core fiber (TCF) and no-core fiber (NCF) coated with α-Fe 2 O 3 /ZrO 2 sensing film is proposed and presented. The single-mode fiber (SMF) is spliced with the TCF and NCF in turn, and a waist-enlarged taper is spliced between them. Then, a silver film is plated on the end face of NCF to enhance the reflection. After the absorption of fluoride ion by the sensing film, the effective refractive index (RI) of the coated cladding will change, which leads to the regular red shift of the interference dip with the increasing fluoride-ion concentration. Thus, the fluoride-ion concentrations can be determined according to the corresponding dip wavelength shifts. The results show that the sensor has an excellent linear response ( R 2 = 0.995) with good sensitivity (8.970 nm/ppm) when the fluoride-ion concentration is in the range of 0–1.5 ppm. The response time is about 15 s. The sensor has the advantage of good selectivity, good temperature and pH stabilities, and can be applied to detect fluoride ion effectively.
✓ 已验证
DOI
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2020
·
IF 3.99
Bao-Shui Wu,Peng Wang,Shu-Hua Teng
Mesoporous carbon-coated iron oxide (α-Fe 2 O 3 @C) nanoparticles were hydrothermally synthesized by using α-Fe 2 O 3 nanospheres (ca. 50 nm) as the cores and resorcinol as the carbon source of the shells. The formation of the mesoporous carbon coatings was confirmed by means of SEM, TEM , FT-IR, TG, XPS and BET measurements. Moreover, the coating thickness was easily adjusted to be 4, 7 and 10 nm by changing the amount of resorcinol. When used as the anodes for lithium-ion batteries (LIBs), the α-Fe 2 O 3 @C nanoparticles exhibited significantly improved electrochemical properties as compared to pure α-Fe 2 O 3 nanoparticles. With the increase of the coating thickness, the α-Fe 2 O 3 @C electrodes presented an initial increase and subsequent decrease in their cycling stability and rate performance. Especially, the α-Fe 2 O 3 @C-7 nanoparticles displayed a high reversible capacity of 1223 mA h/g at 1 A/g, a good cycling stability retaining 1093 mA h/g at 1 A/g after 100 cycles as well as a remarkable rate performance of 570 mA h/g at 5 A/g. The quantitative kinetic analysis revealed that 58 % of the charge storage was contributed by the capacitive process at 0.5 mV/s. The well-defined core-shell structure and superior electrochemical performance of the α-Fe 2 O 3 @C-7 nanoparticles will make them a promising anode for LIBs.
✓ 已验证
DOI
高影响因子
Forensic Toxicology
·
2016
·Vol. 34
·期 2
·398-402
·
IF 0
Shintani-Ishida Kaori,Kakiuchi Yasuhiro,Ikegaya Hiroshi
The toxicological detection of the new synthetic cathinone 4′-methyl-α-pyrrolidinohexanophenone (MPHP) in urine samples has been impossible, because much of MPHP is metabolized before its excretion into urine. In this study, we successfully quantified unmetabolized MPHP in urine of an autopsy case using a sensitive method by liquid chromatography–time-of-flight-mass spectrometry. The quantification method showed good linearity in the range of 1.00–100 ng/mL, and the limit of detection was 0.5 ng/mL in human urine. In the autopsy case, the concentrations of MPHP in urine, plasma, and liver tissue samples were determined to be 60.1, 32.9 ng/mL, and 63.1 ng/g, respectively.
✓ 已验证
DOI
PubMed
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2019
·
IF 4.084
Jiaqin Liu,Chuanyao Liu,Aisheng Huang
Hydrogen has been regarded as the most promising clean and renewable energy. Beside the production of the hydrogen, the separation of hydrogen is also an import issue before it can be used in fuel cells. Membrane-based separation technologies have gained considerable attentions due to its high efficiency and low energy consumption. Zeolite imidazolate framework (ZIF) membranes have drawn intense interest due to their zeolite-like properties such as permanent porosity, uniform pore size and exceptional thermal and chemical stability. It is rather challenged to prepare well-intergrown Co-based zeolitic imidazolate frameworks (ZIFs) membranes on porous α-Al 2 O 3 tubes since Co-based ZIFs prefer to form crystals in the synthesis solution rather than grow as membrane layer on the support surface. In this work, we report the preparation of high-quality ZIF-9 membrane with high H 2 /CO 2 selectivity and excellent thermal stability by using 3-aminopropyltriethoxysilane (APTES) as a covalent linker to modify the α-Al 2 O 3 tube. Due to the formation of covalent bonds between APTES and ZIF-9, ZIF-9 nutrients are bound to the support surface, thus promoting the growth of dense and phase-pure ZIF-9 membrane with a thin thickness of about 4.0 μm. The gas separation performances of the ZIF-9 membrane were evaluated by single gas permeation and mixture gas separation of H 2 /CO 2 , H 2 /N 2 and H 2 /CH 4 , respectively. The mixture separation factors of H 2 /CO 2 , H 2 /CH 4 , and H 2 /N 2 of the ZIF-9 membrane are 21.5, 8.2 and 14.7, respectively, which by far exceeds corresponding Knudsen coefficients. Moreover, the as-prepared ZIF-9 membrane exhibits excellent stability at a relatively broad range of operating temperature, which is beneficial for the industrial application of hydrogen separation or further membrane reactor .
✓ 已验证
DOI
高影响因子
Journal of Environmental Sciences
·
2019
·
IF 3.556
Shanshan Su,Yuyang Liu,Wei He,Xianchun Tang,Wei Jin,Yaping Zhao
Persulfate activation has been applied as one of the efficient advanced oxidation processes (AOPs) to remediate polluted environments. In this study, a novel α-FeOOH anchored by graphene oxide (GO)-carbon nanotubes (CNTs) aerogel (α-FeOOH@GCA) nanocomposite activated persulfate system (α-FeOOH@GCA + K 2 S 2 O 8 ) was applied for decolorization of Orange II (OII). The decolorization of OII was remarkably enhanced to a level of ~ 99% in this system compared with that of pristine α-FeOOH (~ 44%) or GO-CNTs (~ 18%). The enhanced catalytic activity of α-FeOOH@GCA was due to the formation of a heterojunction by α-FeOOH and GO-CNTs as confirmed by the presence of Fe–O–C chemical bonds. The degradation intermediates of OII were comprehensively identified. The proposed degradation pathway of OII begins with the destruction of the conjugated structures of OII by the dominant reactive oxygen species , surface-bound SO 4 •− . The decolorization efficiency of OII by the α-FeOOH@GCA activated persulfate system decreased from the first to third cycle of recycling. Ultraviolet (UV) irradiation or introduction of a small amount of Fe 2+ could restore the activation of this system. The results show that the α-FeOOH@GCA persulfate activation system promises to be a highly efficient environmental remediation method for organic pollutants .
✓ 已验证
DOI
高影响因子
Catalysis Science & Technology
·
2022
·Vol. 12
·期 21
·6384-6397
·
IF 6.177
Zhi Zhu,Reeti Kumar,Liwen Luo,Sunita Varjani,Pengwei Huo,Jonathan Woon-Chung Wong,Jun Zhao
Photocatalytic degradation of pharmaceuticals in the aquatic environment is considered a promising strategy to address water pollution. In this study, a novel photocatalyst was constructed by decorating g-C3N4 (CN) with α-MoC1−x quantum dots (α-MoC1−x-QDs) through a facile calcination method. The catalyst showed enhanced tetracycline (TC) degradation performance under visible light. The unique Mo–N surface bonding states and quantum effect leading to superior TC degradation activity (89.1%) compared to pure CN (21.8%) were reported and revealed. More importantly, the mechanism for the significant enhancement of photocatalytic activity of the catalyst was investigated by DFT (density functional theory) calculations and photo-electrochemistry measurements. The results confirmed that the effect of α-MoC1−x-QDs on CN improved the light absorption capacity obviously, and the Mo–N surface bonding states accelerated the charge migration from CN to α-MoC1−x-QDs. Moreover, the TC degradation pathway, intermediates and photogenerated carrier transfer behaviors were also discussed in depth. This research provides a new strategy for the construction of noble-metal-free co-catalyst/semiconductor composite materials in the photocatalytic degradation of antibiotics.
✓ 已验证
DOI
高影响因子
NEW JOURNAL OF CHEMISTRY
·
2022
·Vol. 46
·期 9
·4272-4282
·
IF 3.925
Yu Lei,Huiqi Wu,Jianfeng Ma,Hao Cheng,Sridhar Komarneni
Layered α-Fe2O3/CuS nanoflowers with abundant active sites were synthesized by a hydrothermal method. The heterogeneous composite catalyst of α-Fe2O3/CuS nanoflowers exhibited a remarkable degradation capacity of 97.8% within 25 min for the Orange II (OII) dye under visible light, which was attributed to the synergistic effect of Na2S2O8 to generate ˙SO4− and ˙OH radicals. The initial pH tests revealed that this system showed better adaptability for its application in a wider pH range (pH = 3–9). In addition, the degradation of different azo dyes such as methylene blue (MB), Orange G (OG) and malachite green (MG) was also studied under the same conditions. The catalyst was characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) to analyze its size, morphology, valence states of elements and chemical components. α-Fe2O3/CuS was further characterized using a vibrating sample magnetometer (VSM) and diffuse reflectance spectroscopy (DRS) to demonstrate its magnetic properties and light absorption capacity. Moreover, α-Fe2O3/CuS showed good recovery and reuse performance as a catalyst after four repeated cycles. A possible mechanism of degradation was proposed by quenching and ESR experiments, which revealed that the highly active species of ˙SO4−, ˙OH and ˙O2− enhanced the photocatalytic performance of the photocatalytic system.
✓ 已验证
DOI
高影响因子
Analytical Methods
·
2016
·Vol. 8
·期 29
·5794-5800
·
IF 1.915
Cunwei Liu,Jinyu Lian,Qiang Liu,Chunli Xu,Baoxin Li
Efficient enantiomer discrimination by a convenient method remains a challenge in biochemical and pharmaceutical fields. Herein we have modified silver nanoparticles (AgNPs) with β-cyclodextrin (β-CD) to obtain a probe for the chiral recognition of aromatic α-amino acids. This assay relies on the distance-dependent optical properties of AgNPs and the difference in inclusion binding strength between the aromatic amino acid enantiomers and the β-CD host. The response of β-CD functionalized-AgNPs to certain chiral aromatic amino acid enantiomers namely D- and L-phenylalanine (Phe), D- and L-tryptophan (Trp), and D- and L-tyrosine (Tyr) in phosphate buffer solutions was studied in detail. In the presence of D-Phe (or L-Trp or L-Tyr), an appreciable yellow-to-red color change of the AgNP solution can be observed, whereas no color change is found in the presence of L-Phe (or D-Trp or D-Tyr). This method can be used to quantitatively determine the percentage of D-Phe in a mixture of D- and L-Phe. The chiral assay described in this work is easily readout with the naked eye or using a cheap UV-vis spectrometer. This method excels by its simplicity, low cost, and good availability of materials.
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）