JOURNAL OF BIOMOLECULAR STRUCTURE & DYNAMICS
·
2018
·
IF 3.107
Manjunath D. Meti,Jialiang Lin,Yuhan Wang,Zhibing Wu,Hong Xu,Xu Xu,Qingguo Han,Ming Ying,Zhangli Hu,Zhendan He
It is well known that Ligupurpuroside B is a water-soluble polyphenolic compound and used to brew bitter tea with antioxidant activities. It acted as a stimulant to the central nervous system and a diuretic (increase the excretion of urine), was used to treat painful throat and high blood pressure, and also exerted weight-loss function. In this regard, a detailed investigation on the mechanism of interaction between Ligupurpuroside B and trypsin could be of great interest to know the pharmacokinetic behavior of Ligupurpuroside B and for the design of new analogues with effective pharmacological properties. Ligupurpuroside B successfully quenched the intrinsic fluorescence of trypsin via static quenching mechanism. The binding constants (Ka) at three temperatures (288, 298, and 308 K) were 1.7841 × 104, 1.6251 × 104 and 1.5483 × 104 L mol−1, respectively. Binding constants revealed the stronger binding interaction between Ligupurpuroside B and trypsin. The number of binding sites approximated to one, indicating a single class of binding for Ligupurpuroside B in trypsin. The enzyme activity result suggested that Ligupurpuroside B can inhibit trypsin activity. Thermodynamic results revealed that both hydrogen bonds and hydrophobic interactions play main roles in stabilization of Ligupurpuroside B-trypsin complex. Circular dichroism (CD) results showed that the conformation of trypsin changed after bound to ligupurpuroside B. Molecular docking indicated that Ligupurpuroside B can enter the hydrophobic cavity of trypsin and was located near Trp215 and Tyr228 of trypsin.Communicated by Ramaswamy H. Sarma
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DOI
高影响因子
ACS Omega
·
2017
·
IF 0
Jie Feng,Yonglei Chen,Yangxia Han,Juanjuan Liu,Sudai Ma,Huige Zhang,Xingguo Chen
In this article, a simple protocol to prepare water-soluble fluorescent copper nanoclusters (CuNCs) using trypsin as a stabilizer and hydrazine hydrate as a reducing agent was reported. It was found that the pH of the reaction solution was critical in determining the fluorescence of CuNCs. CuNCs with blue and yellow fluorescent emission were obtained under basic and acidic conditions, respectively. Although the detailed formation mechanisms of these CuNCs required further analysis, the synthetic route was promising for preparing different fluorescent metal NCs for applications. With good water solubility and excellent photostability, the yellow-emitting CuNCs could serve as a fluorescence probe for detection of Hg2+ based on the aggregation-induced quenching mechanism. The fluorescence quenching efficiency had fantastic linearity to Hg2+ concentrations in the range of 0.1–100 μM, with a limit of detection of 30 nM. Additionally, the yellow-emitting CuNCs exhibited negligible cytotoxicity and were successfully applied to bioimaging of HeLa cells.
研究领域:
纳米技术
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分析化学
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生物医学工程
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材料科学
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DOI
PubMed
Analytical Methods
·
2017
·Vol. 10
·期 4
·459-466
·
IF 1.9
Lingyi Zhang,Bingbing Wang,Shulei Wang,Weibing Zhang
In this work, recyclable trypsin immobilized magnetic nanoparticles based on hydrophilic branched polyethylenimine (PEI) modification were synthesized under mild conditions. The amount of the immobilized enzyme was increased greatly by introducing branched PEI onto poly(methacrylic acid) (PMAA) modified Fe3O4 microspheres (denoted as Fe3O4@PMAA@PEI). Trypsin, a model enzyme for this study, was immobilized by Cu2+ with metal chelation to Fe3O4@PMAA@PEI. Compared with Fe3O4@PMAA nanoparticles, the abundant amino groups of the PEI layer not only increased the amount of the immobilized enzyme, but also improved the hydrophilicity of the material to avoid nonspecific protein adsorption. The performance of this material was evaluated by digesting bovine serum albumin (BSA), myoglobin and cytochrome C, followed by MALDI-TOF-MS analysis. Compared with in-solution digestion, not only the sequence coverage was improved (70.0 ± 3.1% vs. 40.0 ± 2.3% for BSA, 92.0 ± 2.4% vs. 81.0 ± 0.8% for myoglobin and 90.0 ± 3.0% vs. 56.0 ± 1.8% for cytochrome C), but also the digestion time was decreased from 24 h to 10 min. Furthermore, the relative standard deviation values (RSDs) of the sequence coverage of BSA were 3.0% for five consecutive digestions and 2.2% for particles from different batches (n = 3), showing good reproducibility. The Fe3O4@PMAA@PEI-trypsin can endure at least 7 times usage and still maintain good digestion performance after being stored at 4 °C for 25 days. When applied to complex samples, more proteins were identified from the extract of a rat liver than in-solution based digestion (582 vs. 496), with a shorter reaction time of 10 min.
研究领域:
生物化学
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材料科学
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分析化学
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DOI
高影响因子
JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
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2020
·
IF 4.192
Yihui Wang,Yujing Sun,Jie Yang,Lei Dai,Na Ji,Liu Xiong,Qingjie Sun
Nanoparticles (NPs) can form a protein corona (PC) with proteins in biological fluids. We examined whether starch nanoparticles (SNPs) form a PC and interact with digestive enzymes in simulated gastric and intestinal fluids. We investigated the adsorption of pepsin and trypsin on unmodified, carboxyl-, and amino-modified SNPs (SNPs, COOH-SNPs, and NH2-SNPs, respectively). Quartz crystal microbalance data showed that a tight and irreversible pepsin corona formed on the NH2-SNPs, pepsin had little or no binding to the SNPs and COOH-SNPs, and trypsin had weak binding to all three kinds of NPs. Dynamic light scattering data showed that pepsin significantly increased the size of the NH2-SNPs from 120 ± 2.6 to 203 ± 12.2 nm and decreased their surface potential from 23.2 ± 1.0 to 12.7 ± 0.2 mV. NH2-SNPs could induce the fluorescence quenching of pepsin and change its secondary structures without affecting its activity.
研究领域:
食品科学
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生物化学
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DOI
高影响因子
Food & Function
·
2019
·Vol. 10
·期 6
·3291-3302
·
IF 3.241
Guoyan Ren,He Sun,Jinying Guo,Jinling Fan,Gen Li,Saiwen Xu
The molecular mechanism of the interaction between resveratrol and trypsin was studied using fluorescence spectroscopy (intrinsic fluorescence, synchronous fluorescence, three-dimensional fluorescence), ultraviolet-visible (UV-vis) spectroscopy, Fourier transform infrared (FT-IR) spectroscopy and the molecular docking method, as well as through enzyme activity and antioxidant assay. The fluorescence experiments (the Stern–Volmer quenching constants (KSV)) indicated that resveratrol quenched the intrinsic fluorescence of trypsin through the static quenching mechanism. The number of binding sites was about one. The thermodynamic functions ΔG < 0 and ΔH > 0, ΔS > 0 of the binding process, indicating that the combination of the resveratrol and trypsin processes was a spontaneous exothermic reaction and that the hydrophobic effect was the main force between them. UV-vis spectra, synchronous fluorescence spectra and three-dimensional fluorescence spectra analysis showed that the combination of resveratrol and trypsin induced changes in the microenvironment around the fluorophores of trypsin, resulting in alterations in the spatial structure of trypsin. FT-IR spectroscopy indicated that the contents of the α-helixes and β-turns in trypsin decreased and that the contents of the β-sheets, random coils and antiparallel β-sheets increased. All these experimental results were verified and reasonably explained by the molecular docking results. Upon resveratrol and trypsin binding, the enzyme catalytic activity of trypsin and the antioxidant of resveratrol decreased. Results from this study would be useful in elucidating the molecular mechanisms of the interactions between resveratrol and trypsin and contribute to making full use of resveratrol in the food industry.
研究领域:
生物化学
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食品科学
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药理学
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产品关联
DOI
PubMed
高影响因子
Journal of Materials Chemistry B
·
2013
·Vol. 1
·期 17
·2260-2267
·
IF 0
Ying Shen,Wei Guo,Li Qi,Juan Qiao,Fuyi Wang,Lanqun Mao
The effort to stabilize enzymes and improve their activity has generated great interest because of their wide application in proteomics research, bioenergy conversion, bioassays and so on. In this work, biocompatible reactive polymer, poly (glycidyl methacrylate), grafted from magnetic nanoparticles by atom transfer radical polymerization method, has been firstly proposed to immobilize enzymes for microwave-assisted digestion. Meanwhile, trypsin was chosen as a model enzyme. Resulting from the increased functionality, the immobilization amount of the enzyme on the magnetic nanoparticle surface has been greatly improved. Furthermore, the enzyme immobilized magnetic nanoparticles have exhibited excellent repeatability and stability. The influence of the polymer chain length on digestion efficiency has been investigated both at 37 °C and under microwave. It has been found that the digestion efficiency increases with the lengthened polymer brushes due to the increased immobilization amount. Utilizing cytochrome C as a model protein for digestion, the performance of this immobilized biocatalyst has been demonstrated and this digestion assisted with microwave could be completed within 15 s. This study offers insight into the design of polymer brushes on the surface of magnetic nanoparticles for high digestion efficiency in the future.
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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DOI
PubMed
SPECTROSCOPY LETTERS
·
2021
·
IF 1.179
Min Tang,Limin Wang,Guangyao Zhao,Qingguo Han,Xu Xu,Zheling Zeng,Ming Ying,Zhendan He,Zhangli Hu,Hong Xu
The interaction mechanism of a kind of natural drug helicid with typical digestive enzyme trypsin was investigated using multi-spectroscopic techniques and molecular modeling method. The fluorescence quenching experiments showed that helicid quenched trypsin fluorescence via a combined quenching mechanism of both dynamic and static quenching processes because of the formation of the helicid–trypsin complex. Thermodynamic analyses suggested that the binding of helicid to trypsin was entropy-driven, and that hydrophobic interactions are the main force to stabilize the complex. Förster energy transfer theory applied demonstrated that energy transfer occurred within the complex. Ultraviolet-visible spectroscopy, synchronous fluorescence spectroscopy, three-dimension fluorescence spectroscopy together with circular dichroism spectroscopy indicated that the conformation of trypsin changed induced by helicid with the loosening of the polypeptide backbone of trypsin and its partial β-sheet and random coil structures being transformed into an α-helix structure and that helicid was closer to tryptophan residues than to tyrosine residues within the complex. Molecular simulation results explained the above experimental results very well and further implied that besides hydrophobic interactions, hydrogen bonds also helped stabilize the helicid–trypsin complex. This study is helpful to the understanding of the biochemical process of helicid in the human body and could provide useful information for the studies on the structure–bioactivity relationship of natural compounds, as well as the design and optimization of the drugs for the treatments of trypsin overactivity-related diseases.
研究领域:
生物化学
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药物化学
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光谱学
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DOI
高影响因子
MEDICINAL CHEMISTRY RESEARCH
·
2018
·Vol. 27
·期 5
·1549-1557
·
IF 1.607
Liu Ting,Chen Xiaopeng,Xing Jinfeng,Ge Zhiqiang
The changes in activities and conformations of pepsin and trypsin induced by acetazolamide (ACZ) were studied with spectroscopic methods under their respective physiological pH conditions in vitro. The results showed that both the enzymes activities were obviously inhibited as increasing in acetazolamide concentration, while the inhibitory ratio of trypsin was higher than pepsin. The intrinsic fluorescence of the two enzymes was quenched by acetazolamide through static process. Acetazolamide bound trypsin in a more firmly way than pepsin. Thermodynamic analysis revealed that driving force of acetazolamide-pepsin was different from acetazolamide-trypsin. The electrostatic interaction had a significant effect on the binding process of acetazolamide-trypsin, whereas interaction of the acetazolamide-pepsin was driven by hydrogen bonding and van der Waals force. Circular dichroism spectroscopy and synchronous fluorescence showed acetazolamide induced conformational and microenvironmental changes of both the enzymes. These investigations suggested that acetazolamide at different physiological pH may have different effects on the conformations and functions of proteins through variant mechanisms. This study is helpful for understanding the changes in the function and structure of digestive enzymes influenced by acetazolamide in gastrointestinal tract in vivo.
研究领域:
生物化学
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药理学
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酶学
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光谱学
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产品关联
DOI
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
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2014
·
IF 4.331
Yan-Qing Wang,Chun-Yun Tan,Shu-Lin Zhuang,Peng-Zhan Zhai,Yun Cui,Qiu-Hua Zhou,Hong-Mei Zhang,Zhenghao Fei
Being the first-degree toxic pollutants, chlorophenols (CP) have potential carcinogenic and mutagenic activity and toxicity. Since there still lacks studies on molecular interactions of chlorophenols with trypsin, one major binding target of many exogenous environmental pollutants, the binding interactions between five chlorophenols, 2-CP, 2,6-DCP, 2,4,6-TCP, 2,4,6-TCP, 2,3,4,6-TCP and PCP and trypsin were characterized by the combination of multispectroscopic techniques and molecular modeling. The chlorophenols bind at the one main site of trypsin and the binding induces the changes of microenvironment and global conformations of trypsin. Different number of chloride atoms significantly affects the binding and the binding constants K A ranks as K A (2-CP) < K A (2,6-DCP) ≈ K A (2,4,6-TCP) < K A (2,3,4,6-TCP) < K A (PCP). These chlorophenols interacts with trypsin mainly through hydrophobic interactions and via hydrogen bonding interactions and aromatic–aromatic π–π stacking interaction. Our results offer insights into the binding mechanism of chlorophenols with trypsin and provide important information for possible toxicity risk of chlorophenols to human health.
研究领域:
生物化学
·
环境科学
·
毒理学
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产品关联
DOI
PubMed
高影响因子
SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
·
2016
·
IF 2.653
Yingying Liu,Guowen Zhang,Ni Zeng,Song Hu
8-Methoxypsoralen (8-MOP) is a naturally occurring furanocoumarin with various biological activities. However, there is little information on the binding mechanism of 8-MOP with trypsin. Here, the interaction between 8-MOP and trypsin in vitro was determined by multi-spectroscopic methods combined with the multivariate curve resolution-alternating least squares (MCR–ALS) chemometrics approach. An expanded UV–vis spectral data matrix was analysed by MCR–ALS, the concentration profiles and pure spectra for the three reaction species (trypsin, 8-MOP and 8-MOP–trypsin) were obtained to monitor the interaction between 8-MOP and trypsin. The fluorescence data suggested that a static type of quenching mechanism occurred in the binding of 8-MOP to trypsin. Hydrophobic interaction dominated the formation of the 8-MOP–trypsin complex on account of the positive enthalpy and entropy changes, and trypsin had one high affinity binding site for 8-MOP with a binding constant of 3.81 × 10 4 L mol − 1 at 298 K. Analysis of three dimensional fluorescence , UV–vis absorption and circular dichroism spectra indicated that the addition of 8-MOP induced the rearrangement of the polypeptides carbonyl hydrogen-bonding network and the conformational changes in trypsin. The molecular docking predicted that 8-MOP interacted with the catalytic residues His57, Asp102 and Ser195 in trypsin. The binding patterns and trypsin conformational changes may result in the inhibition of trypsin activity. This study has provided insights into the binding mechanism of 8-MOP with trypsin.
研究领域:
生物化学
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药理学
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分子生物学
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产品关联
DOI
PubMed
高影响因子
ACS Applied Materials & Interfaces
·
2017
·
IF 7.504
Long Zhao,Tao Wang,Qiang Wu,Yuan Liu,Zhoujiang Chen,Xiaohong Li
“Turn-on” or “turn-off” probes remain challenges in the establishment of sensitive, easily operated, and reliable methods for in situ monitoring bioactive substances. In the current study, electrospun fibrous strips are designed to provide straightforward observations of ratiometric color changes with the naked eye in the presence of serum heparin or urine trypsin. A tetraphenylethene (TPE) derivative is constructed and along with phloxine B is grafted on fibers, followed by protamine adsorption to induce static quenching of phloxine B and aggregation-induced emission of the TPE derivative. The presence of heparin or trypsin removes protamine to restore the fluorescence of phloxine B at 574 nm (I574) and relieve the emission of the TPE derivative at 472 nm (I472). The grafting densities of phloxine B and the TPE derivative are essential to achieve the optimal fluorescence-intensity ratio of I574/I472 for the ratiometric detection of heparin and trypsin. Under illumination by an ultraviolet lamp, the fibrous mats turn from cyan to green in the presence of heparin at 0.4 U/mL and to a bright yellow at 0.8 U/mL, which is feasible in sensing serum heparin levels during postoperative and long-term care of patients after cardiovascular surgery. The protamine digestion results in similar color transitions with increasing trypsin levels up to 8 μg/mL, indicating the potential for monitoring urine trypsin levels of pancreas transplant patients. The color strips based on the ratiometric fluorescent response indicate advantages in lowering the detection limit and improving the accuracy and reproducibility, bearing great potential for a real-time and naked-eye detection of bioactive substances as self-test devices.
研究领域:
生物医学工程
·
分析化学
·
材料科学
·
生物化学
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产品关联
DOI
PubMed
高影响因子
FOOD HYDROCOLLOIDS
·
2018
·
IF 5.089
Jia-Nan Yan,Meng Zhang,Jun Zhao,Yue Tang,Jia-Run Han,Yi-Nan Du,Hui Jiang,Wen-Gang Jin,Hai-Tao Wu,Bei-Wei Zhu
In order to provide a foundation for comprehensive utilization of scallop (Patinopecten yessoensis) , the gel properties of hydrolysates from scallop male gonad (SMGHs) were studied. The hydrolysates were obtained from scallop male gonads (SMGs) by using trypsin. The changes in molecular mass of proteins were determined by SDS-PAGE and HPLC with a peptide separation column. The gel properties of SMGHs were investigated by using rheometer and texture instrument in comparison with that of ι-carrageenan and gelatin . The results showed that the proteins of SMGs were significantly degraded after hydrolysis with trypsin at a dosage of 3000 U/g protein. The SMGHs showed an appearance of gelation after hydrolysis for 30–180 min and cooling down. Under various sweep models, the values of storage modulus ( G′ ), loss modulus ( G″ ), viscosity ( ƞ ) of SMGHs were obvious higher than those of SMGs. The textural parameters containing firmness, cohesiveness and adhesive force of SMGHs at dosages of 50 and 75 mg/mL were similar to those of ι-carrageenan and gelatin at 25 mg/mL, respectively. For the mixtures, the gel property of SMGHs/ι-carrageenan SMGHs/gelatin increased significantly. The low-field NMR (LF-NMR) also reflected the T 23 of SMGHs/ι-carrageenan, T 21 of SMGHs/ι-carrageenan and SMGHs/gelatin mixture decreased significantly in comparison with SMGHs alone. These results suggest that SMGHs could be applied as a potential gelling and thickening agent in food formulations.
研究领域:
食品科学
·
海洋生物学
·
蛋白质化学
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产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）