Molecular Catalysis
·
2022
·
IF 5.089
Changhui Zhu,Kaiqiang Wang,Jia Luo,Baohe Tian,Jialin Sun,Xinhong Liu,Wenchao Zhu,Zhiyun Zou
α -Aromatic amino acid esters are important platform compound for drugs, sweeteners and fluorescent sensors. Due to the amphoteric dissociation and steric effect, the esterification of α -aromatic amino acids is difficult. Here, a green and efficient solid superacid, SO 4 2− -S 2 O 8 2− /SnO 2 -Nd 2 O 3 (SSSN), was synthesized and firstly used for the methyl esterification of α -aromatic L-tyrosine and L-tryptophan. The methyl esters yield was optimized with the highest L-TyrOMe yield of 93.1% and L-TrpOMe yield of 92% over SSSN-650 (SO 4 2− -S 2 O 8 2− /SnO 2 -Nd 2 O 3 calcined under 650 °C). Furthermore, it was clarified that the doping of Nd enhanced the electron-withdrawing inductive effect of SO 4 2− /S 2 O 8 2− with increased Brønsted and Lewis acidity, which were beneficial to the esterification of L-tyrosine and L-tryptophan. Besides, Nd-doping reduced the activation energy during L-Tyr esterification by kinetics study. Finally, SSSN-650 could be recycled six times with > 70% of their initial ester yield. The decrease of catalyst activity was caused by carbon deposition and species leaching. This work launched a novelty, rapid and environmental-benign technology for the esterification of α -aromatic amino acid using solid superacid.
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FOOD CHEMISTRY
·
2023
·
IF 8.8
Caiyun Cheng,Chao Yuan,Bo Cui,Jianpeng Li,Guimei Liu
β-Cyclodextrin (β-CD) Pickering emulsion and cinnamaldehyde/β-cyclodextrin (CIN/β-CD) Pickering emulsion were prepared and the influences of oxidation and digestion were investigated. CIN/β-CD composite was better dispersed at the oil–water interface than β-CD. Hydrophobic group of CIN anchored in the oil phase and Hydrophilic hydroxyl group of β-CD extended into the aqueous phase, which allowed CIN/β-CD composite to be oriented at the oil–water interface and formed a more stable oil–water interface layer. β-CD Pickering emulsion was more susceptible to oxidative deterioration than CIN/β-CD Pickering emulsion, its malondialdehyde (MDA) value was as high as 509.41 ± 9.37 nmol/L. Digestion experiment indicated that CIN/β-CD Pickering emulsion was released inner oil phase in the small intestine and free fatty acid (FFA) release rate was 44.32 ± 1.08%. Pharmacokinetic parameters manifested that α-tocopherol peak concentration (C max ) was 64.32 ± 6.45 mg/L and the peak time (T max ) appeared at 5 h after administration of CIN/β-CD Pickering emulsion.
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Molecular Catalysis
·
2023
·
IF 4.6
Qinzhe Lin,Xuanjin Lv,Xianming Zeng,Mengning Zhong,Qiyun Wu,Huilin Ren,Shenpeng Xu,Wentian Chen,Wenting Du,Jun Li
The potential applications of imine reductases (IREDs) in chiral amine synthesis have garnered significant attention. However, there is still limited research on IRED for reacting with bulky substrates. In this study, we addressed this gap by mutating engineered IRED M5 when confronted with a bulky amine substrate, α-methylphenylethylamine. Our investigation revealed the relatively low catalytic efficiency of engineered IRED M5 when tasked with α-methylphenylethylamine. To enhance the catalytic performance of IRED M5, the mutants M203V and F260A were obtained by rational design. F260A exhibited a substantial improvement in the conversion of tert‑butyl 3-((( R )-1-phenylethyl)amino)piperidine-1-carboxylate, exceeding 2-fold. This enhancement suggests that the F260A mutation likely led to a more conducive active site or increased substrate binding affinity. Furthermore, F260A demonstrated a significant enhancement in stereoselectivity when applied to tert‑butyl 4-((( S )-1-phenylethyl)amino)azepane-1-carboxylate, with the enantiomeric excess ( e.e. ) increasing from 9% to 86% ( S ). M203V increased conversions for 3-((( R / S )-1-phenylethyl)amino)piperidine-1-carboxylate. In addition, we revealed a possible the underlying molecular mechanism of the effect of F260A and M203V on catalytic performance. Our study provides a deeper understanding of the rational design according to the interaction between IRED cavity and substrate.
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ACS Catalysis
·
2023
·
IF 12.9
Luyao Guo,Xiaoyan Liu,Ziang Zhao,Ronghe Lin,Yu Meng,Xinzheng Ma,Yihui Li,Xiaoling Mou,Li Yan,Hejun Zhu,Yunjie Ding
Nanostructured bimetallic Pt–Bi catalysts are designed by defect engineering of N-doped carbons as the hosts. The optimal catalyst delivers good yields (>98%) in the direct oxidation of C5–C9 linear α-alcohols to corresponding fatty acids, significantly outperforming activated carbon-supported benchmarks and rivaling the state-of-the-art systems. A combined kinetic and computational study on n-heptanol oxidation as a model reaction unveils the kinetic and thermodynamic origins of the better performance of the PtBi alloy than neat or Bi-modified Pt(111) surfaces. Structure–performance correlations further identify that the metal particle size, surface Bi/Pt ratio, and strong basicity strongly influence the catalyst performance in alcohol oxidation. The creation of nitrogen defects facilitates the formation of the surface PtBi alloy and brings strong basicity, accounting for the boosted performance. These findings enable a step closer toward the manufacture of valuable fatty acids from abundant coal by coupling the advanced oxidation with the recently piloted higher alcohol synthesis via the Co–Co2C-catalyzed Fischer–Tropsch reaction.
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MATERIALS RESEARCH INNOVATIONS
·
2015
·
IF 0.83
D. H. He,A. P. Tang,Q. W. Zhong,Z. Q. He,G. R. Xu,H. S. Song
Porous α-LiVOPO4/C composite was prepared by the solution combustion synthesis method followed by annealing at 500°C for a short annealing duration of just 50 min. The synthesised material was characterised by XRD, SEM, TEM, N2 adsorption–desorption isotherms and charge–discharge tests. When tested at 0.05C rate for Li ion insertion properties, α-LiVOPO4/C composite exhibits good cycle capability with an negligible capacity degradation for the first 31 cycles. However, it shows poor rate capability with initial discharge specific capacities of 127.6 mAh g− 1 (0.05C), 109.1 mAh g− 1 (0.1C) and 74.9 mAh g− 1 (0.2C), respectively.
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CHINESE JOURNAL OF CHEMICAL ENGINEERING
·
2023
·
IF 3.8
Renwen Tian,Yan Sun
Extensive use of polyethylene terephthalate (PET) has brought about global environmental problems. A recently reported PET hydrolase (PETase) discovered from Ideonella sakaiensis showed high potential for degrading PET at moderate temperatures, but its activity and stability need further improvement for practical applications. Herein, we proposed to use α-synuclein (αS) as a fusion chaperone and created six PETase-αS fusion enzymes with linkers of different types and lengths. All the fusion enzymes exhibited improved enzymatic performance, presenting 1.5 to 2.6-fold higher activity towards bis-2(hydroxyethyl) terephthalate than PETase, as well as significantly increased stabilities. Fluorescence spectroscopy indicated that the chaperone fusion tightened the overall conformation and resulted in the opening of the substrate binding pocket, which led to the improved thermal stability and catalytic activity of the fusion enzymes. Remarkably, one of the fusion proteins, PETase-[(GS)(EK)] 10 -αS, showed 3.2 to 5.1 times higher PET degradation capability than PETase. The significantly boosted PET degradation performance was not only attributed to the enhanced enzymatic activity and stability, but also possibly due to the binding affinity of the fused αS domain for PET. These findings demonstrated that αS was an effective fusion chaperone for significantly enhancing the enzymatic performance of PETase.
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Foods
·
2023
·Vol. 12
·期 15
·2866
·
IF 5.2
Kexin Dai,Jiangpeng Wang,Yingting Luo,Yaqi Tu,Fazheng Ren,Hao Zhang
The characteristics and the functions of Maillard reaction products (MRPs) produced by polydextrose (PD), a new type of prebiotic, and α-lactalbumin (α-LA) were valued. PD and α-LA were incubated at 60 °C and 79% relative humidity for up to 72 h to prepare MRPs. The results showed that the absorbance and fluorescence intensity of heated α-LA-PD increased, and the amount of free amino groups reduced as the reaction progressed, which confirmed the formation of different stages of MRPs. Electrophoresis revealed an increase in molecular mass and the degree of covalent cross-linking. The secondary structure of MRPs experienced no significant changes with the measurement of circular dichroism (CD), while the tertiary structure gradually unfolded, exposing hydrophobic groups. Furthermore, a significant increase was detected in the radical-scavenging activity of 2,2-diphenyl-1-picrylhydrazyl (DPPH) and the ferric reducing/antioxidant power (FRAP) of MRPs. The findings offer a foundation for understanding the structural and functional features of MRPs in formula milk powder.Keywords:polydextrose;α-lactalbumin;Maillard reaction;hydrophobicity;antioxidant activity
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PubMed
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Marine Drugs
·
2023
·Vol. 21
·期 5
·286
·
IF 5.4
Jianying Dong,Panpan Zhang,Junjie Xie,Ting Xie,Xiaopeng Zhu,Dongting Zhangsun,Jinpeng Yu,Sulan Luo
α4/6-conotoxin TxID, which was identified fromConus textile, simultaneously blocks rat (r) α3β4 and rα6/α3β4 nicotinic acetylcholine receptors (nAChRs) with IC50values of 3.6 nM and 33.9 nM, respectively. In order to identify the effects of loop2 size on the potency of TxID, alanine (Ala) insertion and truncation mutants were designed and synthesized in this study. An electrophysiological assay was used to evaluate the activity of TxID and its loop2-modified mutants. The results showed that the inhibition of 4/7-subfamily mutants [+9A]TxID, [+10A]TxID, [+14A]TxID, and all the 4/5-subfamily mutants against rα3β4 and rα6/α3β4 nAChRs decreased. Overall, ala-insertion or truncation of the 9th, 10th, and 11th amino acid results in a loss of inhibition and the truncation of loop2 has more obvious impacts on its functions. Our findings have strengthened the understanding of α-conotoxin, provided guidance for further modifications, and offered a perspective for future studies on the molecular mechanism of the interaction between α-conotoxins and nAChRs.Keywords:α-conotoxin TxID;α3β4 nAChR;loop size modification;electrophysiology;CD spectra
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FOOD CHEMISTRY
·
2023
·
IF 8.8
Huan Li,Jichen Yang,Mengfan Wang,Xiangzhao Ma,Xin Peng
Biflavonoids are a kind of polyphenol compounds with numerous biological functions. However, the potential inhibitory activities of biflavonoids on α-glucosidase are yet unknown. Here, the inhibitory effects of two biflavonoids (amentoflavone and hinokiflavone) on α-glucosidase and their interaction mechanisms were explored using multispectral approaches and molecular docking. The results showed that the inhibitory activities of biflavonoids were much better compared with monoflavonoid (apigenin) and acarbose, and the order of inhibition ability was hinokiflavone > amentoflavone > apigenin > acarbose. These flavonoids were noncompetitive inhibitors of α-glucosidase and showed synergistic inhibition effects with acarbose. Additionally, they could statically quench the intrinsic fluorescence of α-glucosidase, and form the non-covalent complexes with enzyme primarily through hydrogen bonds and van der Waals forces. The binding of flavonoids changed the conformational structure of α-glucosidase, therefore impairing the enzyme activity. The findings suggested that biflavonoids could be considered as potential hypoglycemic functional foods in diabetes therapy.
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Advanced Healthcare Materials
·
2023
·
IF 10
Xiang Xu,Jinjuan Ma,Yubin Zheng,Shaolei Wang,Aiguo Wang,Nan Zheng
Aggregation caused quenching (ACQ) effect can severely inhibit the application of hydrophobic photosensitizers (PSs) bearing planar and rigid structures. Most of the reported cases utilized random-coiled polymers for the in vivo delivery of PSs, which would inevitably aggravate ACQ effect due to the flexible chains. In this work, the role of polymers’ secondary structures (especially α -helical conformation) in overcoming the PSs’ aggregation is systemically investigated based on the design of α -helical polypeptides bearing tetraphenylporphyrin (TPP) side chains. Atomistic molecular dynamics simulation, fluorescence quantum yield, and reactive oxygen species (ROS) generation yield are evaluated to demonstrate that α -helical polypeptide backbones can significantly boost both fluorescence quantum yield and ROS by suppressing the π - π stacking interaction between TPP units. The enhanced in vitro and in vivo phototoxicity for helical polypeptides also revealed functions of secondary structures in inhibiting ACQ and improving the membrane activity. Successful in vivo photodynamic therapy (PDT) results in mice bearing H22 tumors showed great potentials for further clinical applications.
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INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2019
·
IF 4.784
Chao Peng,Junfei Xu,Guangxue Chen,Junfei Tian,Minghui He
A series of highly porous and biocompatible poly (vinyl alcohol) (PVA) hydrogels containing partially deacetylated α-chitin nanowhiskers (ChWs) were fabricated by the double-cross-link (DC) with glutaraldehyde (GA) and repeating freeze-thawing cycle. Then these hydrogels were used as carrier for bovine serum albumin (BSA), which served as the model drug. The nanowhiskers worked effectively to raise the mechanical property of the PVA/ChWs hydrogels. This property increased significantly from 1.55 to 26.59 MPa with the increase of the ratio of ChWs to PVA from 0% to 40%. Additionally, the morphological properties of the gel matrix were comprehensively investigated. The results showed that the novel ChWs/PVA hydrogels were facilely constructed from sequential chemical cross-linking and physical cross-linking with GA. The hydrogel with the ChWs to PVA weight ratios of 40% achieved the highest equilibrium swelling ratio, and could release more than 80% of the BSA from its gel matrix within 75 h.
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Journal of Water Process Engineering
·
2018
·
IF 0
Chenlu Ye,Kang Hu,Zhijuan Niu,Yiran Lu,Lin Zhang,Kai Yan
One-step controllable synthesis of rhombohedral α-Fe 2 O 3 photocatalyst has been successfully developed by P123 soft template assisted method. A combination analysis of XRD, BET, SEM and HRTEM has documented that P123 surfactant plays a crucial role in the controllable synthesis of rhombohedral α-Fe 2 O 3 with the exposure of (110) and (012). The as-obtained α-Fe 2 O 3 material is efficient for the photocatalytic degradation of Bisphenol A (BPA). About 91% of BPA (30 mg/L) was degraded by using 1 g/L α-Fe 2 O 3 within 6 h under the simulated sunlight irradiation, which was almost twice higher than that of commercial Fe 2 O 3 . More importantly, reaction intermediates (e.g., 4, 4′-methylenediphenol, phenol and lactic acid) were confirmed by LC–MS/MS analysis, and the rational pathway of BPA degradation was finally proposed.
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危险品化学品经营许可证（带存储）