AMINO ACIDS
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2020
·Vol. 52
·期 11
·1479-1489
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IF 3.063
Yang Sheng-Yuan,Liu Shu-Min,Wu Yan-Yan,Lin Qian,Liang Gui-Lian,Liu Jiao-Fen,Liang Zi-Zhan,Liang Jia-Rong
Glutamate decarboxylase (GAD, EC 4.1.1.15) is an important enzyme in gamma-aminobutyric acid biosynthesis and DL -glutamic acid resolution. In this study, the Enterococcus faecium -derived GAD was successfully immobilized by regenerated chitin (RC) via specific adsorption of cellulose-binding domain (CBD). The optimal binding buffer was 20 mmol/L phosphate buffer saline (pH 8.0), and the RC binding capacity was 1.77 ± 0.11 mg cbd-gad /g rc under this condition. The ratio of wet RC and crude enzyme solution used for immobilization was recommended to 3:50 (g/mL). To evaluate the effect of RC immobilization on GAD, properties of the immobilize GAD (RC-CBD-GAD) were investigated. Results indicated RC-CBD-GAD was relatively stable at pH 4.4–5.6 and temperature − 20–40 °C, and the optimal reaction pH value and temperature were pH 4.8 and 50 °C, respectively. When it was reacted with 5 mmol/L of follow chemical reagents respectively, the activity of RC-CBD-GAD was hardly affected by EDTA, KCl, and NaCl, and significantly inactivated by AgNO 3 , MnSO 4 , MgSO 4 , CuSO 4 , ZnSO 4 , FeCl 2 , FeCl 3 , AlCl 3 , CaCl 2, and Pb(CH 3 COO) 2 . The apparent K m and V max were 28.35 mmol/L and 147.06 μmol/(g RC-CBD-GAD ·min), respectively. The optimum time for a batch of catalytic reaction without exogenous pH control was 2 h. Under this reaction time, RC-CBD-GAD had a good reusability with a half-life of 23 cycles, indicating that it was very attractive for GABA industry. As a novel, efficient, and green CBD binding carrier, RC provides an alternative way to protein immobilization.
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Journal of Oleo Science
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2020
·
IF 1.304
Maomao Kou,Siting Feng,Nanjing Zhong
In this study, Lecitase® Ultra (LU) was immobilized onto the parent and the amino-functionalized SBA-15. The immobilization conditions were studied and the activity of the parent SBA-15 supported LU (SBA-15-LU) was found to be at 2177.78 ± 101.84 U/g. After 3-aminopropyl and n-(2-aminoethyl)-3-aminopropyl groups functionalization, enzymatic activity was increased to 3555.56 ± 200.21 and 3444.44 ± 346.41 U/g respectively. The immobilized LU samples were then used to catalyze glycerolysis. The possibility for diacylglycerols (DAG) and monoacylglycerols (MAG) production was evaluated and it was found only suitable for DAG production. In addition, the glycerolysis activity of the immobilized LU was impaired by the tert-pentanol and solvent-free was found suitable. Similar DAG content over 50 wt% could be obtained from glycerolysis by the three immobilized LU samples. The reusability in glycerolysis was evaluated, and 9.79 % of the initial glycerolysis activity was remained from the SBA-15-LU after 5 cycles of reuse. Encouragingly, after 3-aminopropyl and n-(2-aminoethyl)-3-aminopropyl groups functionalization, 62.93 and 83.91% of their initial activity was respectively remained after 5 cycles of reuse.
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CHINESE JOURNAL OF CHEMICAL ENGINEERING
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2020
·
IF 2.627
Xiao Liang,Qing Li,Zhiyuan Shi,Shaowei Bai,Quanshun Li
Enzyme immobilization has been accepted as an efficient technique for improving the stability and recyclability of enzymes. Herein, biomimetic mineralization strategy was employed to achieve the immobilization of urease in a type of metal–organic frameworks (zeolite imidazolate framework-8, ZIF-8), and the immobilized enzyme urease@ZIF-8 was systematically evaluated for its structure, activity, stability and recyclability, using the hydrolysis of urea as a model. The entrapment of urease was found to be realized in a synchronous manner with the formation of ZIF-8 crystal. The loading of urease in ZIF-8 was measured to be ca. 10.6% through the bicinchoninic acid (BCA) protein assay. The encapsulated urease could efficiently maintain its native conformation, which endowed the immobilized urease with excellent activity and stability, even in harsh conditions ( e.g. , in the presence of trypsin, acidic or alkali conditions, or at high temperature). Further, urease@ZIF-8 exhibited good recyclability during the degradation of urea, in which it could keep 58.86% of initial activity after being used for 5 cycles. Thus, biomimetic mineralization could be potentially utilized as a promising method to prepare immobilized ureases with superior activity, stability and recyclability, thereby facilitating the construction of efficient catalysts for industrial biocatalysis and biosensing.
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Materials Science & Engineering C-Materials for Biological Applications
·
2020
·
IF 5.88
Xinxin Chen,Xiang Wang,Siyu Wang,Xiuhang Zhang,Jiaao Yu,Ce Wang
There has been a recent increase in research interest regarding the development of wound dressings containing bioactive compounds capable of improving outcomes for complex healing needs. In the present study, we describe the generation of bromelain immobilized eletrospun poly(ε-caprolactone) (PCL) fibers (BrPDA-PCL fibers) using the dopamine-assisted co-deposition strategy. We wanted to combine the structural advantage of electrospun fiber and the activity of bromelain and PDA to develop functional wound dressings. We found that bromelain activity could be better stabilized when via its immobilization on electrospun fibers. The resultant BrPDA-PCL fibers exhibited promising properties including optimal mechanical stability, wettability, and rates of water vapor transmission. In addition, these BrPDA-PCL fibers were biocompatible, allowing for effective cellular adhesion and proliferation. The results of zone of inhibition testing further confirmed that these fibers achieved effective antibacterial activity against Escherichia coli and Staphylococcus aureus . When used in vivo, as compared with PCL fibers or control animals the BrPDA-PCL fibers enhanced wound healing rates while reducing associated inflammation. As such, these results indicate that these biocompatible BrPDA-PCL fibers exhibit desirable physicochemical properties making them ideal for use as a wound dressing to enhance the repair of full-thickness wounds to the skin.
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Inorganic Chemistry Frontiers
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2020
·Vol. 7
·期 17
·3146-3153
·
IF 5.958
Shu-Fan Li,Xue-Jing Zhai,Chong Zhang,Hui-Lin Mo,Shuang-Quan Zang
Enzyme immobilization in hierarchically porous metal–organic frameworks (HP–MOFs) has attracted extensive attention in biocatalysis and contaminant biodegradation. However, the small-dimension mesopores and micropores on the exterior of MOFs are incompatible with large-sized enzymes, thus limiting the further enhancement of mass transfer efficiency and enzyme accessibility. Herein, we encapsulated horseradish peroxidase (HRP) in highly ordered macro–micropore zeolitic imidazolate framework-8, in which the encapsulated enzyme not only fully preserved its catalytic activity, but also exhibited long-term stability, recyclability, low leakage, and resistance to chelating compounds. Through enzyme immobilization, we significantly enhanced the biodegradation process of hazardous dyes probably as a result of the pre-concentration of the dye reactant for the combination of enzymes and MOFs. This work shows the great potential of constructing highly functional biocatalysts in three-dimensional ordered macro–micropore MOFs with enhanced mass diffusion efficiency, which is promising for applications to biodegradation of all sorts of other organic pollutants in water resources.
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SOLID STATE SCIENCES
·
2018
·
IF 1.861
Jianyi Liu,Yan Liu,Dianxin Jin,Minjia Meng,Yinhua Jiang,Liang Ni,Zhanchao Liu
Tannic-acid-templated large pore mesoporous silica nanoparticle (LMSN) was synthesized using one-pot procedure and the external surface was further modified with APTES (LMSN-N) to immobilize trypsin. After modification, trypsin was difficult to be immobilized on the outer surface of the LMSN due to the electrostatic repulsion. Naturally, study of the trypsin immobilized in the interior pores could be implemented solely. Meanwhile, the activity of immobilized trypsin was optimized by response surface method (RSM), and the ANOVA was employed to explore the interaction between independent variables. The maximum enzyme activity (12.28 U/mg) was obtained under a certain condition that the quality of T-LMSN-N-272 was 153 μg, the pH was 7.9, and the temperature was 40.4 °C. Simultaneously, the immobilized enzyme was proved to possess better thermal stability, storage stability and recycling performance than free enzyme.
研究领域:
生物化学
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材料科学
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酶工程
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JOURNAL OF MOLECULAR CATALYSIS B-ENZYMATIC
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2016
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IF 2.189
Feng Zhang,Ruonan Wang,Cheng Zhen,Bin Li
Novel magnetic cellulose nanocrystals (MCNCs) prepared via electrostatic self-assembly approach were used as magnetic carriers for efficient immobilization of papain and facilitated recovery of this immobilized enzyme. Zeta potential measurements, Fourier transform infrared spectroscopy and Scanning electron microscope were applied to evaluate the forming mechanism and surface structure of MCNCs. Cellulose nanocrystals (CNCs) were successfully combined with cationic polyethyleneimine (PEI) modified Fe 3 O 4 nanoparticles (NPs), and the electrostatic interaction between them was a key driving force. The prepared MCNCs were successfully used for the immobilization and separation of papain from the reaction system. When enzyme concentration and pH value of enzyme solution were 0.4 mg mL −1 and 6, respectively, the resultant immobilized enzyme exhibited the highest enzymatic activity about 227 μg min −1 g −1 . Better pH and thermo stabilities than those of the free papain were also achieved after immobilizing the enzyme on MCNCs. Furthermore, the immobilized papain manifested enhanced tolerability to three different solvents, namely n -butyl alcohol, n -hexane and [Cnpy][NTf 2 ], respectively. The prepared MCNCs as the efficient carrier materials have a strong application potential for enzyme immobilization.
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COLLOIDS AND SURFACES B-BIOINTERFACES
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2023
·
IF 5.8
Dahai Jiang,Ting Xu,Honggang Xiao,Wangbo Xu,Qingqing Zhu,Dong Liu,Yong Chen,Hanjie Ying,Huanqing Niu,Ming Li
This study developed a surface functionalized lignin-based sub-microsphere as an innovative support for enzyme immobilization . Lignin was first modified with a silane reagent leading to lignin/SiO 2 (LS) organic/inorganic hybrid particles, displayed as regular sub-micro spheres with a SiO 2 shell as demonstrated in SEM images. The LS particles were further modified to introduce nickel ions , as evidenced in XPS spectra , facilitating affinity adsorption with a his-tagged enzyme . The immobilization of adenylate cyclase from Haloactinopolyspora alba (HaAC), expressed in Escherichia coli , was conducted on the surface functionalized LS (LS-G-NTA-Ni). The immobilization conditions were optimized to achieve the highest relative activity, which were determined to be using a Ni 2+ concentration of 62.5 mM, at pH=9.5 and 25 °C, with an enzyme-to-support ratio of 4.0 for a duration of 2 h. The immobilized HaAC shows maximum relative activity at pH=9.5 and 40 °C, and exhibits significantly improved thermal stability compared to the free enzyme. After undergoing five reusing cycles, the immobilized HaAC maintains a satisfactory activity (54.15%), which is due to the surface chemistry and the structural stability of the functionalized LS. This work provides a valuable exploration for high-value application of industrial lignin.
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Nature Communications
·
2023
·Vol. 14
·期 1
·1-13
·
IF 16.6
Wang Shenqiang,Zhang Ying,Wang Yanfang,Yang Yinxian,Zhao Sheng,Sheng Tao,Zhang Yuqi,Gu Zhen,Wang Jinqiang,Yu Jicheng
Immune checkpoints play key roles in maintaining self-tolerance. Targeted potentiation of the checkpoint molecule PD-L1 through in situ manipulation offers clinical promise for patients with autoimmune diseases. However, the therapeutic effects of these approaches are often compromised by limited specificity and inadequate expression. Here, we report a two-step dual-anchor coupling strategy for enhanced immobilization of PD-L1 on target endogenous cells by integrating bioorthogonal chemistry and physical insertion of the cell membrane. In both type 1 diabetes and rheumatoid arthritis mouse models, we demonstrate that this approach leads to elevated and sustained conjugation of PD-L1 on target cells, resulting in significant suppression of autoreactive immune cell activation, recruitment of regulatory T cells, and systematic reshaping of the immune environment. Furthermore, it restores glucose homeostasis in type 1 diabetic mice for over 100 days. This specific in situ bioengineering approach potentiates the functions of PD-L1 and represents its translational potential.
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JOURNAL OF INORGANIC BIOCHEMISTRY
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2023
·
IF 3.9
Pengfei Shi,Ziyong Wu,Yingyan Liu,Guoda Zhang,Chuangli Zhang
Bio-enzymes have the advantages of strong substrate specificity, high catalytic efficiency, and minimal toxic side effects, making them promising drugs in cancer therapy. However, the poor stability and cellular penetrability of uncoated protein in the physiological environment severely restricts the direct application of Bio-enzyme. To address it, we report a metal-organic framework (MOF), Hf-DBA (H 2 DBA, biphenyl carboxylic acid ligands). The morphology of the Hf-DBA was revealed by TEM and the diameter was in the range of 200 to 350 nm. Hf-DBA acted a carrier for intracellular delivery and protection of horseradish peroxidase (HRP). The prepared HRP@Hf-DBA can catalyze the excess H 2 O 2 in the tumor cells to generation of •OH for chemodynamic therapy (CDT). Compared with free HRP, the catalytic activity of HRP@Hf-DBA is significantly improved, and the optimal catalytic conditions are explored. The catalytic stability of HRP@Hf-DBA remained above 70% after 12 cycles of catalysis. After treatment with HRP@Hf-DBA, the apoptosis rates of A549 and Hela cells was 71.64%, and 76.86%. The results in vitro show that HRP@Hf-DBA can effectively inhibit the growth of tumor cells through enhanced CDT.
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RSC Advances
·
2015
·Vol. 5
·期 48
·38665-38672
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IF 3.84
Zhen Lei,Xia Liu,Lina Ma,Dianjun Liu,Haifei Zhang,Zhenxin Wang
In this work, spheres-on-sphere (SOS) silica microspheres are prepared via a facile one-pot synthesis. After functionalization with carboxyl groups, the carboxylated SOS silica microspheres (SOS-COOH microspheres) can serve as a support for horseradish peroxidase (HRP) covalent immobilization. The obtained enzyme hybrid (SOS-COOH-HRP) is more stable under alkaline conditions than the free counterpart, and exhibits longer-term storage stability and higher resistance toward the denaturing agents such as guanidine hydrochloride (GdmCl) and urea. The Michaelis–Menten constant (Km) of the immobilized enzyme is decreased slightly while the maximum rate of reaction (Vmax) is very close to that of free HRP, resulting in the catalytic efficiency of SOS-COOH-HRP being enhanced significantly. For evaluating its utility, a SOS-COOH-HRP-based colorimetric method has been developed for selectively and sensitively detecting H2O2 both in buffer and 10% diluted human serum. Furthermore, the SOS-COOH-HRP displays excellent reusability and reproducibility in cycle analysis. The results demonstrate that the SOS-COOH-HRP has great potential for practical applications in biosensing and industrial fields.
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ACS Applied Materials & Interfaces
·
2023
·
IF 9.5
Xiuli Wang,Weiwei Fei,Zhifan Zhou,Mengjing Zhu,Yinghao Chang,Qilin Guo,Jia Guo,Changchun Wang
Magnetic-assisted DNA testing technology has attracted much attention in genetics, clinical diagnostics, environmental microbiology, and molecular biology. However, achieving satisfying DNA adsorption and desorption efficiency in real samples is still a big challenge. In this paper, a new kind of high-quality magnetic composite microsphere of MM@PGMA–PA-Ti4+ was designed and prepared for DNA extraction and detection based on the strong interaction of Ti4+ and phosphate groups. By taking the advantages of high magnetic susceptibility and high Ti4+ content, the MM@PGMA–PA-Ti4+ microspheres possessed remarkable extraction capacity for mimic biological samples (salmon sperm specimens) with saturated loadings up to 533.0 mg/g. When the DNA feeding amount was 100 μg and the MM@PGMA–PA-Ti4+ dosage was 1 mg, the adsorption and desorption efficiencies were 80 and 90%, respectively. The kinetic and equilibrium extraction data were found to fit well with the pseudo-second-order model and Freundlich isotherm model. Furthermore, the MM@PGMA–PA-Ti4+ microspheres were successfully employed for DNA extraction from mouse epithelial-like fibroblasts. The extraction ability (84 ± 4 μg/mg) and DNA purity were superior to the comparative commercial spin kits, as evaluated by electrophoresis assays and qPCR analysis. The experimental results suggest that the MM@PGMA–PA-Ti4+ microspheres possess great potential as an adsorbent for DNA purification from complex biological samples.
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