ENZYME AND MICROBIAL TECHNOLOGY
·
2024
·
IF 3.4
Lili Zhang,Yu Hong,Jiapeng Lu,Yi Wang,Wei Luo
Transaminases (EC 2.6.1.X, TAs) are important biocatalysts in the synthesis of chiral amines, and have significant value in the field of medicine. However, TAs suffer from low enzyme activity and poor catalytic efficiency in the synthesis of chiral amines or non-natural amino acids, which hinders their industrial applications. In this study, a novel TA derived from Paracoccus pantotrophus ( pp TA) that was investigated in our previous study was employed with a semi-rational design strategy to improve its enzyme activity to 2-ketobutyrate. By using homology modeling and molecular docking, four surrounding sites in the substrate-binding S pocket were selected as potential mutational sites. Through alanine scanning and saturation mutagenesis, the optimal mutant V153A with significantly improved enzyme activity was finally obtained, which was 578 % higher than that of the wild-type pp TA (WT). Furthermore, the mutant enzyme pp TA-V153A also exhibited slightly improved temperature and pH stability compared to WT. Subsequently, the mutant was used to convert 2-ketobutyrate for the preparation of L-2-aminobutyric acid (L-ABA). The mutant can tolerate 300 mM 2-ketobutyrate with a conversion rate of 74 %, which lays a solid foundation for the preparation of chiral amines.
研究领域:
生物化学
·
酶工程
·
药物合成
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DOI
PubMed
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2023
·
IF 4.2
Zhangyi Gao,Yue Tian,Ping Liu,Linjing Jiang,Lili Gao,Le Du,Jiqin Zhu
3,3-Dimethyl-2-butyl ketone (pinacolone) has received attention for its important role in organic synthesis. However, existing techniques to synthesize pinacolone come with low yields, which are detrimental to the subsequent purification and economic benefits of enterprises. In this study, a scale-up method based on mixing enhancement was developed to improve the synthesis of pinacolone from isoamylene without significant scaling-up effects. Reaction conditions such as temperature, reaction time, and molar ratios were systematically investigated in a microchannel reactor and a batch reactor. A maximum yield of 91% was obtained under batch conditions. On the basis of the proposed scale-up method, an 87% yield was achieved after a 50-fold volume scale-up. A simplified kinetic model (0.56 order with respect to 2-chloro-2-methylbutane) was also established.
研究领域:
有机化学
·
化工工程
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DOI
高影响因子
CRYSTAL RESEARCH AND TECHNOLOGY
·
2025
·
IF 1.9
Yansheng Jiang,Wei Wei,Hangwei Jia,Muhammad Arif,Zhihua Yang,Xiuling Yan,Xueling Hou
With the continuous development of optical science and technology, there are higher requirements for the versatility and multi-application scenarios of optical devices. Organic–inorganic hybrid birefringent crystals have attracted much attention due to their high flexibility in molecular design and assembly. In this work, an alkaline earth metal 2-hydroxybutanedioate Ba 3 (C 4 H 4 O 5 ) 2 (OH) 2 crystallizing in the C 2/ c space group is synthesized by the hydrothermal method. Its unit cell parameters are a = 20.0584(7) Å, b = 7.4499(3) Å, c = 9.5087(3) Å, and β = 96.808(2) °. Ba 3 (C 4 H 4 O 5 ) 2 (OH) 2 polycrystalline powder is characterized in detail by Fourier transform infrared (FTIR) absorption spectroscopy, UV–vis–NIR diffuse reflectance spectroscopy, and simultaneous thermal analysis. In addition, theoretical analyses are carried out using first-principles calculations and Hirshfeld surface analysis. The theoretical birefringence of Ba 3 (C 4 H 4 O 5 ) 2 (OH) 2 is calculated to be 0.1 @546 nm. At the same time, UV–vis–NIR diffuse reflectance and band structure calculations show that Ba 3 (C 4 H 4 O 5 ) 2 (OH) 2 has an indirect bandgap of 5.11 eV with a UV cutoff edge of 203 nm. By leveraging the complementary attributes of organic and inorganic materials, Ba 3 (C 4 H 4 O 5 ) 2 (OH) 2 stands out as a promising UV birefringent candidate.
研究领域:
材料科学
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光学工程
·
凝聚态物理
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无机化学
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晶体工程
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DOI
高影响因子
RSC Advances
·
2025
·Vol. 15
·期 14
·10862-10872
·
IF 4.6
Muneera Alrasheedi,Salah M. El-Bahy,Refat El-Sayed,Khaled F. Debbabi,Alaa S. Amin
Although modern reported methods, such as AAS, ICP-AES, ICP-MS, have good sensitivity, the high cost of equipment, the need for sophisticated instruments, separation and preconcentration steps and experienced technicians along with lack of precise methods make them cumbersome. Solid phase extraction (SPE) emerges as an attractive technique that reduces solvent consumption, minimizes exposure, shortens extraction time, and lowers disposal costs. Herein, a pioneering methodology for the quantification of minute amounts of silver is introduced, using 2-nitro-6-(thiazol-2-yl-diazenyl)phenol (NTDP) as a complexing agent and Triton X-100 as a nonionic surfactant within a ternary surfactant system at a pH of 5.3. This novel extraction strategy demonstrated selective preconcentration. The enriched solution was subjected to spectrophotometric analysis for the quantification of the analyte. After refining extraction and complexation parameters, a remarkable 250-fold increase in the enrichment factor was attained, highlighting a sensitivity boost of 509 times compared with traditional extraction approaches relying solely on nonionic surfactants. The key parameters of molar absorptivity and Sandell sensitivity were determined to be 6.04 × 106 L mol−1 cm−1 and 0.0018 ng cm−2, respectively. The calibration plot was observed from 5.0–175 ng mL−1, whereas Ringbom optimum concentrations ranged from 15–160 ng mL−1. The detection and quantification limits were 1.63 and 4.95 ng mL−1, respectively. The relative standard deviation (RSD) of the complex was 2.27. The suggested method was efficiently utilized for assessing the Ag+ concentration in real samples, producing acceptable outcomes.
研究领域:
分析化学
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环境科学
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产品关联
DOI
PubMed
高影响因子
MICROCHIMICA ACTA
·
2019
·Vol. 186
·期 5
·1-9
·
IF 5.479
Chen Dan,Xu Hui
The exploration of monohydroxy polycyclic aromatic hydrocarbons and 8-hydroxy-2′-deoxyguanosine (8-OHdG) produced by oxidative stress and DNA damage is a powerful and non-invasive tool to study the health risk of exposure to polycyclic aromatic hydrocarbons (PAHs). A nanocomposite prepared from graphene oxide, poly(3,4-ethylenedioxythiophene) and polypyrrole was electrodeposited on the internal surface of a stainless-steel tube for online in-tube solid phase microextraction (IT-SPME) of 8-OHdG, 3-hydroxyphenanthrene and 1-hydroxypyrene from urine. The coating possesses excellent chemical and mechanical stability, high extraction efficiency, good resistance to matrix interference, and a long lifespan. An online IT-SPME-high performance liquid chromatography-mass spectrometry method was developed for the determination of these three metabolite biomarkers in human urine. Figures of merit include (a) enrichment factors of 30–48; (b) low limits of detection (4–41 pg·mL −1 at S/ N = 3); (c) wide linear ranges (0.05–50 ng·mL −1 ); (d) good recoveries from spiked samples (71.6–109.5%); and (e) acceptable repeatability (2.3–14.6%). The method offers the advantages of low cost, simplicity, sensitivity, rapidity and automation.
Schematic illustration of online in-tube solid phase microextraction using graphene oxide/poly(3,4-ethylenedioxythiophene)/polypyrrole composites as adsorbent in a stainless-steel (SS) tube for the enrichment and simultaneous determination of 8-hydroxy-2′-deoxyguanosine, 3-hydroxyphenanthrene and 1-hydroxypyrene prior to HPLC-MS analysis.
研究领域:
分析化学
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环境健康
·
毒理学
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DOI
PubMed
高影响因子
BIOLOGICAL & PHARMACEUTICAL BULLETIN
·
2020
·
IF 1.863
Yuanguo Xiong,Hao Lu,Hanlin Xu
Hepatic fibrosis (HF) is a common disease, with currently no available treatment. Galangin, a natural flavonoid extracted from Alpinia officinaruim Hance, has multiple effects demonstrated in previous studies. The aim of the present study was to explore the anti-fibrogenic effect of galangin in vitro, and research its potential molecular mechanisms. LX-2 cells were chosen as an in vitro HF model, and were treated with galangin in different concentrations. Cell viability was analyzed using Cell Counting Kit-8 (CCK-8) and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, cell apoptosis was measured using flow cytometry, and the anti-fibrogenic effect of galangin was determined using quantitative reverse transcription polymerase chain reaction (RT-qPCR), immunofluorescence, and western blotting. The results show that the proliferation of LX-2 cells was efficiently inhibited by galangin, and apoptosis was induced in a dose-dependent manner. Both the mRNA and protein expression of α-SMA and collagen I were markedly downregulated. Galangin also inhibited the PI3K/Akt and Wnt/β-catenin signaling pathways and increased the Bax/Bcl-2 ratio. The results of this study suggest that galangin has an anti-fibrogenic effect and may represent a promising agent in the treatment of hepatic fibrosis.
研究领域:
药理学
·
细胞生物学
·
分子生物学
·
肝病学
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DOI
PubMed
高影响因子
ENERGY & FUELS
·
2017
·
IF 3.091
Yamin Cheng,Mengyun Zhao,Chao Zheng,Sai Guo,Xiaohong Li,Zhijun Zhang
2-acrylamido-2-methyl-1-propanesulfonic acid sodium (AMPS) was grafted onto the surface of reactive nanosilica (RNS-D) by free radical polymerization to afford RNR-D/PAMPS inorganic–polymer nanohybrid with good water dispersibility, which can serve as a potential oil displacement agent for enhanced oil recovery. The RNS-D/PAMPS nanoparticles were characterized by transmission electron microscopy and Fourier transform infrared spectrometry, and the oil displacement performance of the RNS-D/PAMPS nanohybrid solution was evaluated by static and dynamic oil displacement tests. Results showed that the RNS-D/PAMPS nanohybrid as the potential oil displacement agent could obviously reduce the interfacial tension between crude oil and water, increase the hydrophilicity of rock surface, and dramatically decrease the adhesion work of crude oil and rock. When the RNS-D/PAMPS solution is introduced at a mass fraction of 5.0% under static and dynamic oil displacement tests, the tested crude oil can be recovered at a total rate of up to 87.67% and 92.86%, respectively, showing promising potential in enhanced oil recovery.
研究领域:
化学工程
·
石油工程
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DOI
高影响因子
BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR BASIS OF DISEASE
·
2019
·
IF 4.328
Wenbin Hua,Shuai Li,Rongjin Luo,Xinghuo Wu,Yukun Zhang,Zhiwei Liao,Yu Song,Kun Wang,Kangcheng Zhao,Shuhua Yang,Cao Yang
Intervertebral disc degeneration (IVDD) is a well-known cause of lower back pain. Icariin has been shown to exert a protective effect on human nucleus pulposus (NP) cells and accordingly has implications for the prevention and treatment of IVDD; however, the molecular mechanisms underlying its action are not fully established. In this study, the mechanisms underlying its protection against hydrogen peroxide (H 2 O 2 )-induced oxidative stress injury were investigated. In vitro, we demonstrated that icariin inhibits H 2 O 2 -induced mitochondria-mediated apoptosis. It upregulates oxidative stress mediators, i.e., reactive oxygen species, and downregulates mitochondrial membrane potential. Nuclear factor erythroid 2-related factor 2 (Nrf-2) is a key factor involved in the regulation of the endogenous defense system. It was proved that icariin could activate the Nrf-2 signaling pathway, upregulate the protein expression of nuclear respiratory factor-1 and the mitochondrial transcription factor, promoting mitochondrial biogenesis in human NP cells. An Nrf-2 agonist and inhibitor promoted or partly abolished the protective effects of icariin on mitochondrial homeostasis. Moreover, it was demonstrated that the Nrf-2 signaling pathway could be inhibited by the phosphatidylinositol 3-Kinase/AKT pathway. In vivo, icariin ameliorated IVDD in a rat model by promoting Nrf-2 activity, and preserving extracellular matrix in NP cells. These data suggest that icariin could ameliorate IVDD in rat models in vivo. In summary, the protective effects of icariin on human NP cells may suppress the pathogenesis of IVDD via the Nrf-2 signaling pathway. Our findings suggest that the Nrf-2 signaling pathway is a novel therapeutic target for the treatment of IVDD.
研究领域:
神经科学
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药理学
·
细胞生物学
·
分子生物学
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DOI
PubMed
高影响因子
JOURNAL OF CHEMICAL THERMODYNAMICS
·
2021
·
IF 3.178
Xuemei Zhang,Feiyan Yang,Chungui Jian,Hongwei Wang,Wangxin Kong,Guangjin Shangguan,Meifang Xia
Liquid-liquid equilibrium (LLE) data for the ternary system of (2-methyl-2-butanol + water + n -octanol) were determined at 303.15 K, 313.15 K, and 323.15 K under atmospheric pressure. The Hand equation, the Othmer-Tobias equation, and the mass balance between the feed and the conjugated phases were used to test the reliability of the experimental LLE data. The results show that the correlation coefficients ( R 2 ) of the equations are close to 1, and the relative error of mass balance is less than 0.5%. The selectivity ( S ) was used to evaluate the capacity of n -octanol to extract 2-methyl-2-butanol from the water, which is much greater than 1. Furthermore, S decreases with the mass fraction of 2-methyl-2-butanol in the aqueous phase and increases with equilibrium temperature. The NRTL and UNIQUAC models were applied to correlate the experimental LLE data, and the binary interaction parameters were obtained. The root-mean square deviations (RMSDs) for the two models obtained are less than 1.1%.
研究领域:
化学工程
·
物理化学
·
热力学
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DOI
高影响因子
EUROPEAN JOURNAL OF MEDICINAL CHEMISTRY
·
2018
·
IF 4.816
Yong-Yu Qi,Qian Gan,Ya-Xian Liu,Ya-Hong Xiong,Zong-Wan Mao,Xue-Yi Le
In the search for more effective anticancer drugs with less toxic side effects, dipeptides were introduced into the Cu(II) complex of 5-methyl-2-(2′-pyridyl)benzimidazole (HPBM). Analytical and spectroscopic techniques were employed to thoroughly characterize complexes [Cu(Gly-gly)(HPBM)(H 2 O)]ClO 4 ·0.5H 2 O ( 1 ) and [Cu(Gly- L -leu)(HPBM)(H 2 O)]ClO 4 ( 2 ) (where Gly-gly = Glycyl-glycine anion, Gly- L -leu = Glycyl- l -leucine anion). The solution stability studies performed by ultraviolet–visible (UV–Vis) spectroscopy confirmed the stability of the complexes in the buffer solutions. The DNA binding affinity was evaluated using multi-spectroscopy, viscosity measurement and molecular docking methods and further quantified by K b and K app values, revealing an intercalative mode. Moreover, gel electrophoresis analysis revealed that the complexes could damage CT DNA through a hydroxyl radical pathway in the presence of ascorbic acid . All the complexes displayed favorable antimicrobial and cytotoxic activities toward the tested microorganisms ( Bacillus subtilis , Staphylococcus aureus , Escherichia coli and Pseudomonas aeruginosa ) and cancer cells (A549, HeLa and PC-3). Most importantly, the possible anticancer mechanism of the complexes was explored by determining the cells morphological changes, intracellular reactive oxygen species (ROS) levels, location in mitochondria, mitochondrial membrane potentials and the expression of Bcl-2 family proteins. The results showed that the complexes could induce apoptosis in HeLa cells through an ROS-mediated mitochondrial dysfunction pathway, which was accompanied by the regulation of Bcl-2 family proteins.
研究领域:
化学
·
药理学
·
分子生物学
·
癌症研究
·
微生物学
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产品关联
DOI
PubMed
高影响因子
ENVIRONMENTAL POLLUTION
·
2020
·
IF 6.793
Cui Ma,Shengyong Jia,Pengfei Yuan,Zhengguang He
Composite magnetic oxide at cow dung ash, nano-Fe 3 O 4 @cow dung ash (nano-Fe 3 O 4 @CDA), was used as catalytic material for the degradation of 2, 2′-methylenebis (4-methyl-6-tert-butylphenol) (AO 2246) in real biologically pretreated landfill leachate . The Fe 3 O 4 @CDA composite exhibited catalytic ozonation activity and allowed material separation and magnetic recovery. The effects of several operating parameters including O 3 concentration, catalyst dosage, temperature and scavengers were evaluated in parallel. Over 70% of AO 2246 were removed by the nano-Fe 3 O 4 @CDA/O 3 system under optimum conditions within 120min reaction time. The EPR, GC–MS and free-radical quenching experiments expatiated the mechanism of this degradation process. It was confirmed that the AO 2246 was degraded efficiently in this catalytic micro-ozonation process, Additionally, GC–MS analysis state clearly that the 3,5-bis(1,1-dimethylethyl)phenol, 4-(1,5-dihydroxy-2,6,6-trimethylcyclohex-2-enyl)but-3-en-2-one, ethanone, 1-(1,4-dimethyl-3-cyclohexen-1-yl)-, 5-tert-butyl-6-3, 5-diene-2-one, 2-hydroxyhexanoic acid, 2-propenoic acid 1,1-dimethylethyl ester, butanoic acid, 2-methyl-, methyl ester and propanoic acid, 2, 2-dimethyl- were the dominant oxidation products (OPs) during the degradation of the AO 2246. The EPR results showed that the catalytic ozonation over Fe 3 O 4 @CDA led to produce more hydroxyl radicals , which were in favor of AO 2246 degradation. The toxicity evolution was also performed through a QSAR analysis calculated by the ECOSAR program which further demonstrated the different responses toward the AO 2246 and its OPs.
研究领域:
环境科学
·
化学工程
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DOI
PubMed
高影响因子
Food Analytical Methods
·
2017
·Vol. 10
·期 10
·3434-3442
·
IF 2.038
Hu Kai,Deng Zhifen,Li Sui,Wu Mingxia,Liu Wei,Zhang Shusheng
In this study, bis(tetraoxacalix[2]arene[2]triazine) modified silica gel was successfully prepared and used as an efficient sorbent for solid-phase extraction. Coupled with ultra-high pressure liquid chromatography (UHPLC), the extraction performance of the sorbent was evaluated by using three flavonoids as model analytes. Main parameters, which affecting extraction efficiency were carefully optimized. The results showed that multiple intermolecular interactions were involved in the sample pretreatment procedure, including π–π, hydrophobic and hydrogen bonding interactions. Under the optimal conditions, the proposed method was applied for the analysis of three flavonoids in grape juice. Satisfactory linear ranges for flavonoids were obtained in the range of 5–200 ng mL −1 for quercetin, 1–200 ng mL −1 for luteolin, and 2–200 ng mL −1 for kaempferol, with good correlation coefficients (>0.9996). Limits of detection (LODs) were in the range of 0.5–2 ng mL −1 , and the LOQs were between 1 and 5 ng mL −1 . The recovery values of spiked grape juice ranged from 97 to 106% with relative standard deviations (RSDs) less than 4.7% ( n = 3). This method exhibited the advantages of simplicity, rapidity, and low solvent consumption, and was promising for the separation and determination of flavonoids in grape juice and other matrixes.
研究领域:
分析化学
·
食品科学
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DOI
高影响因子
危险品化学品经营许可证（带存储）