ENZYME AND MICROBIAL TECHNOLOGY
·
2021
·
IF 3.493
Li-Bin Guo,Chen-Yuan Zhu,Yi-Bei Wu,Xiao-Man Fan,Ye-Wang Zhang
Chondroitin AC lyase can efficiently hydrolyze chondroitin sulfate (CS) to low molecule weight chondroitin sulfate, which has been widely used in clinical therapy, including anti-tumor, anti-oxidation, hypolipidemic, and anti-inflammatory. In this work, a novel chondroitin AC lyase from Pedobacter xixiisoli ( Px chonAC) was cloned and overexpressed in Escherichia coli BL21 (DE3). The characterization of Px chonAC showed that it has specific activities on chondroitin sulfate A, Chondroitin sulfate C and hyaluronic acid with 428.77, 270.57, and 136.06 U mg −1 , respectively. The K m and V max of Px chonAC were 0.61 mg mL -1 and 670.18 U mg -1 using chondroitin sulfate A as the substrate. The enzyme had a half-life of roughly 660 min at 37 °C in the presence of Ca 2+ and remained a residual activity of 54 % after incubated at 4 °C for 25 days. Molecular docking revealed that Asn123, His223, Tyr232, Arg286, Arg290, Asn372, and Glu374 were mainly involved in the substrate binding. The enzymatic hydrolysis product was analyzed by gel permeation chromatography, demonstrating Px chonAC could hydrolyze CS efficiently.
研究领域:
生物化学
·
酶学
·
药理学
·
微生物学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
·
2022
·
IF 4.831
Zhendong Fu,Feng Guo,Jiahe Qiu,Runchi Zhang,Mingxu Wang,Liping Wang
2-Methylimidazole (MIM) is a classic organic ligand that shows excellent thermal stability and chemical robustness and is widely used in ZIFs. Recently, transformations of MOFs have been realized by using metals or ligands. In this study, we propose a new strategy—adjusting MIM by extending the alkyl chain length —to change the properties of related MOFs. Furthermore, we used copper as the metal core to replace zinc to mimic the active sites of laccases (electron transfer between copper and imidazole ring). As a result, the nanostructures transformed from nanoleaves to nanovesicles, which changed the Cu(II)/Cu(I) ratio from 3.7 to 1.7, as well as the lattice constant (decreased the diffraction angle) and enzyme-like activity (inhibition). In addition, we revealed that superoxidase anions were the main factors responsible for its laccase-like activity. We applied it to detect and discriminate phenolics. Laccase-mimicking activity was best at pH 7.0. When compared to protein laccase, the Cu-MeIm nanozyme had a greater Vmax at the same mass concentration. It was used to identify and distinguish phenolics. In the presence of Cu-MeIm nanozymes, the linear range is 0.1–2 mM and the detection limit of 2,4-DCP is 0.034 mM.
研究领域:
材料科学
·
纳米技术
·
分析化学
·
生物化学
·
酶学
✓ 已验证
DOI
高影响因子
ANALYTICAL AND BIOANALYTICAL CHEMISTRY
·
2022
·Vol. 414
·期 22
·6611-6620
·
IF 4.478
Tang Yulian,Lv Xue,Gou Wenxin,Zhou Xuemei,Hao Junkai,Feng Jing,Qi Yuji,Hu Lei,Yan Zhengquan
Dopamine (DA) is an important neurotransmitter; however, any excess or deficiency of DA will cause several diseases in humans. To monitor DA efficiently and conveniently, a Ag nanozyme strengthened by bioactive folic acid (FA@AgNPs) was developed by homogeneous redox assembly. After the microstructure and performance were characterized in detail, it was noted that the proposed FA@AgNPs possessed superior peroxidase-like activity due to the ultra-small Ag nanoparticles and multiple amino, hydroxyl, and aromatic rings in FA. FA@AgNPs accelerated the oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) with a low Michaelis constant ( K m ) and high maximal reaction rate ( V max ). Importantly, the characteristic absorbance intensity of FA@AgNPs-TMB-H 2 O 2 at 652 nm ( A 652 ) was exclusively deteriorated in the presence of trace DA, accompanied by a visual color change from blue to colorless. Under the optimized conditions (pH 4.0, 300 μL 1.5 mM TMB, 300 μL 1.0 M H 2 O 2 and incubated for 30 min at room temperature), there expressed an excellent linear relationship between lg A 0 / A 652 and c DA from 1.0 ×10 −8 to 6.67×10 −6 mol/L with a low limit detection of 7.1×10 −10 mol/L (S/N=3). When applied for monitoring of DA in real fruit juice and pharmaceutical samples, the recovery was between 96.6% and 104.9%, with RSD less than 2.2%. The enhanced peroxidase-like activity of the FA@AgNP system and its selective recognition mechanism for DA are also proposed. Graphical abstract
研究领域:
纳米技术
·
生物化学
·
分析化学
·
神经科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Food Bioscience
·
2021
·
IF 4.24
Jiao Yuan,Yuvaraj Ravikumar,Guoyan Zhang,Junhua Yun,Yufei Zhang,Hossain M. Zabed,Xianghui Qi
l -arabinose isomerases (L-AIS) are enzymes that mediate the conversion of l -arabinose into l -ribulose and D-galactose into D-tagatose. The potential of L-AI from Lactobacillus parabuchneri CICC 6004 (LPAI) in D-galactose biotransformation using E. coli whole-cells was studied. The parameters investigated in this study were 1) the optimum pH, temperature, and cofactor specificity for maximum enzyme activity ; 2) the D-tagatose biosynthesis from D-galactose using whole-cells containing LPAI. The results showed that with D-galactose, the purified LPAI showed the highest activity, 15.52 U/mg at pH 6.7, 45 °C, and necessitates 3 mM Ca 2+ as its cofactor. The K m , V max and K cat /K m values of LPAI for D-galactose were 5.4 mM, 35.5 U/mg and 2.8 mM −1 min −1 , respectively, while the respective values for l -arabinose were found to be 4.3 mM, 63.1 U/mg and 5.9 mM −1 min −1 .The applicability of LPAI for D-tagatose synthesis was shown by using whole-cell biocatalyst approach. Under the optimum conditions, during one-stage biotransformation of D-galactose by E. coli whole cells, 39.0 g/L of D-tagatose was produced from 140 g/L of D-galactose after 50 h, which corresponded to the yield and productivity of 0.28 g/g and 0.78 g/L/h, respectively. Further addition of new cells into the reaction mixture in the second stage produced 54.0 g/L of D-tagatose after 100 h. The D-tagatose total yield and productivity were 0.39 g/g and 0.54 g/L/h, respectively. The results attained in this study showed LPAI as a potential candidate for the industrial production of D-tagatose.
研究领域:
生物化学
·
生物技术
·
酶学
·
微生物学
✓ 已验证
DOI
高影响因子
ANALYTICA CHIMICA ACTA
·
2022
·
IF 6.911
Xue Wang,Futing Wen,Liu He,Jiangyu Su,Ping Jiang,Daiping He
Defects engineering as an effective strategy was widely utilized to modulate catalytic performance for heterogeneous catalysts through tuning surface electronic surface and creating more active sites. In this work, porous Co–Mn oxide nanosheets with abundant oxygen vacancies (OVs-CMO NSs) were prepared via a simple “one-stone-two-birds” method. OVs were verified by various characterizations and found more favorable for O 2 absorption and activation to produce more reactive O2•- radical, resulting in an improved oxidase-like activity in initiating 3,3′,5,5′-tetramethylbenzidine (TMB) oxidation , with a lower K m value of 0.00717 mM and a higher V max of 2.086 × 10 −7 M/s. Since heparin (Hep) shows an inhibition effect on OVs-CMO NSs-TMB chromogenic system due to strong absorption, a colorimetric sensing platform for Hep detection was established. The present colorimetric detection shows high sensitivity, good selectivity and reliability for normal goat serum. This work not only provides a high-performance non-precious metal oxidase mimic prepared by simple surface defect engineering, but also builds a sensitive colorimetric method for Hep detection.
研究领域:
材料科学
·
纳米技术
·
分析化学
·
生物化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY
·
2024
·
IF 6.2
Bu-Da Su,Xiao-Meng Li,Zhi-Wei Huang,Yue Wang,Jia Shao,Yan-Yan Xu,Le-Xin Shu,Yu-Bo Li
Ochratoxin A (OTA) is a common fungal toxin frequently detected in food and human plasma samples. Currently, the physiologically based toxicokinetic (PBTK) model plays an active role in dose translation and can improve and enhance the risk assessment of toxins. In this study, the PBTK model of OTA in rats and humans was established based on knowledge of OTA-specific absorption, distribution, metabolism, and excretion (ADME) in order to better explain the disposition of OTA in humans and the discrepancies with other species. The models were calibrated and optimized using the available kinetic and toxicokinetic (TK) data, and independent test datasets were used for model evaluation. Subsequently, sensitivity analyses and population simulations were performed to characterize the extent to which variations in physiological and specific chemical parameters affected the model output. Finally, the constructed models were used for dose extrapolation of OTA, including the rat-to-human dose adjustment factor (DAF) and the human exposure conversion factor (ECF). The results showed that the unbound fraction (F up ) of OTA in plasma of rat and human was 0.02–0.04% and 0.13–4.21%, respectively. In vitro experiments, the maximum enzyme velocity (V max ) and Michaelis–Menten constant (K m ) of OTA in rat and human liver microsomes were 3.86 and 78.17 μg/g min −1 , 0.46 and 4.108 μg/mL, respectively. The predicted results of the model were in good agreement with the observed data, and the models in rats and humans were verified. The PBTK model derived a DAF of 0.1081 between rats and humans, whereas the ECF was 2.03. The established PBTK model can be used to estimate short- or long-term OTA exposure levels in rats and humans, with the capacity for dose translation of OTA to provide the underlying data for risk assessment of OTA.
研究领域:
毒理学
·
药代动力学
·
食品安全
·
生物医学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
PROTEIN EXPRESSION AND PURIFICATION
·
2022
·
IF 2.025
Xiaowen Wang,Sibo Chen,Lin Fan,Hao Liu,Si Chen,Xianfeng Ye,Zhoukun Li,Zhongli Cui,Yan Huang
A new glycoside hydrolase family 2 (GH2) β-galactosidase encoding gene galM was cloned from Microvirga sp. strain MC18 and overexpressed in Escherichia coli . The recombinant β-galactosidase GalM showed optimal activity at pH 7.0 and 50 °C, with a stability at pH 6.0–9.0 and 20–40 °C, which are conditions suitable for the diary environment. The K m and V max values for o-nitrophenyl-β- d -galactopyranoside (oNPG) were 1.30 mmol/L and 15.974 μmol/(min·mg), respectively. GalM showed low product inhibition by galactose with a K i of 73.18 mM and high tolerance for glucose that 86.5% activity retained in the presence of 500 mM glucose. It was also stable and active in 20% of methanol, ethanol and isopropanol. In addition, the enzyme activity of GalM was activated significantly over 0–2 mol/L NaCl (1.6–4.3 fold). These favorable properties make GalM a potential candidate for the industrial application.
研究领域:
生物化学
·
酶学
·
生物技术
✓ 已验证
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）