SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
·
2011
·
IF 1.77
Ying Liu,Rongxiang Cao,Pengfei Qin,Rutao Liu
Because of the widespread concern that persistent organic pollutants (POPs) may be adversely affecting the health of humans, reliable assessing their toxic effects is urgently needed. We selectively study the interaction between dicofol (DCF) and trypsin by steady state and time resolved fluorescence quenching measurements and UV–visible absorption spectroscopy under physiological conditions as well as applying molecular docking method to establish the interaction model. The fluorescence results indicate DCF can spontaneously form a complex with trypsin mainly by hydrogen bond with only one binding site, which had been validated in molecular docking. The conformational change of trypsin was proved by UV–visible absorption and synchronous fluorescence spectroscopy indicating a red shift of carbonyl absorption peak. All the results indicated DCF had potential toxic effects on both the structure and activity of the enzyme trypsin and the effects enhanced with the increasing concentration of DCF.
研究领域:
环境生物学
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生物化学
·
毒理学
✓ 已验证
DOI
PubMed
高影响因子
JOURNAL OF NANOPARTICLE RESEARCH
·
2017
·Vol. 19
·期 7
·1-13
·
IF 2.02
Qin Dezhi,Wang Li,Wang Yabo,Du Xian,Zhang Li,Zhang Qiuxia,He Bingyu
Protein-conjugated CdS nanocrystals (NCs) with different morphology have been synthesized under biomimetic condition using trypsin as capping agent in aqueous medium. The reaction parameters including concentration of trypsin, pH value, reaction time, and temperature have a major influence on the morphology and optical property of CdS NCs. XRD, selected area electron diffraction (SAED), TEM, HRTEM, and EDS characterizations were used to investigate the structure, composition, morphology, and size of as-prepared products. The binding reaction between Cd 2+ /CdS and trypsin was investigated systematically through various spectroscopic methods. UV-vis, FT-IR, photoluminescence (PL) spectra, and conductivity analysis of Cd 2+ -trypsin suggest that Cd 2+ ions could coordinate with the functional groups of trypsin and induce the formation of unfolding and loosening structure in protein molecules, and the change of protein conformation was also verified by circular dichroism (CD) spectra. This interaction increased local supersaturation of Cd 2+ ions around the groups of trypsin and reduced the nucleation activation energy of CdS nuclei, which favored heterogeneous nucleation in trypsin matrix and resulted in the formation of inorganic-organic hybrid materials. The functional integrity of the enzyme conjugated to CdS NCs was studied by monitoring the enzymatic activity of CdS-trypsin conjugates. The fluorescence of CdS NCs is dependent strongly on trypsin which passivates the surface of NCs.
研究领域:
生物化学
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材料科学
·
光谱学
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产品关联
DOI
高影响因子
MICROCHIMICA ACTA
·
2018
·Vol. 185
·期 8
·1-7
·
IF 5.705
Hu Yanling,He Yu,Han Yaxue,Ge Yili,Song Gongwu,Zhou Jiangang
Stable copper nanoclusters (CuNCs) were prepared by utilizing D-penicillamine as both the stabilizer and reductant. The emission of the CuNCs (with excitation/emission peaks at 390/645 nm) is largely stabilized by coating with poly(sodium-p-styrenesulfonate) (PSS). Cytochrome c (Cyt c) quenches the fluorescence of the PSS-coated CuNCs, and this effect was exploited to design a quenchometric fluorometric assay for Cyt c. If trypsin is added to the loaded CuNCs, it will hydrolyze Cyt c to form peptide fragments, and fluorescence is gradually restored. A highly sensitive and fluorometric turn-off-on assay was constructed for sequential detection of Cyt c and trypsin. The linear ranges for Cyt c and trypsin are from 8.0 nM to 680 nM, and from 0.1 to 6.0 μg mL −1 , and the lower detection limits are 0.83 nM and 20 ng mL −1 for Cyt c and trypsin, respectively.
Schematic illustration of the fluorometric assay for trypsin based on the electron transfer between poly(p-styrenesulfonate)-protected copper nanoclusters (PSS-CuNCs) and cytochrome c (Cyt c).
研究领域:
分析化学
·
生物化学
·
纳米技术
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产品关联
DOI
PubMed
高影响因子
CHEMICO-BIOLOGICAL INTERACTIONS
·
2021
·
IF 5.194
Jing Wang,Xinping Yu,Xiaolin Zheng
Doping quantum dots (QDs) with extra element presents a promising future for their applications in the fields of environmental monitoring, commercial products and biomedical sciences. However, it remains unknown for the influence of doping on the molecular biocompatibility of QDs and the underlying mechanisms of the interaction between doped-QDs and protein molecules. Using the “one-pot” method, we synthesized N-acetyl- l -cysteine capped CdTe: Zn 2+ QDs with higher fluorescence quantum yield, improved stability and better molecular biocompatibility compared with undoped CdTe QDs. Using digestive enzyme trypsin (TRY) as the protein model, the interactions of undoped QDs and Zn-doped QDs with TRY as well as the underlying mechanisms were investigated using multi-spectroscopy, isothermal titration calorimetry and dialysis techniques. Van der Waals forces and hydrogen bonds are the major driving forces in the interaction of both QDs with TRY, which leading to the loosening of protein skeleton and tertiary structural changes. Compared with undoped QDs, Zn-doped QDs bind less amount of TRY with a higher affinity and then release higher amount of Cd. Zn-doped QDs have a less stimulating impact on TRY activity by decreasing TRY binding and reducing Cd binding to TRY. Taken all together, Zn-doped QDs offer a safer alternative for the applications of QDs by reducing unwanted interactions with proteins and improving biocompatibility at the molecular level.
研究领域:
生物化学
·
纳米医学
·
环境科学
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产品关联
DOI
PubMed
高影响因子
SENSORS AND ACTUATORS B-CHEMICAL
·
2018
·
IF 5.667
Xiaoyun Lin,Zhenmao Zhu,Chengfei Zhao,Shaoguang Li,Qicai Liu,Ailin Liu,Liqing Lin,Xinhua Lin
In this study, we developed a simple, sensitive and label-free colorimetric sensor for trypsin and its inhibitor using oxidase mimicking activity of protamine-stabilized platinum nanoparticles units (Pro-PtNPs units). Protamine is designed to stabilize PtNPs and served as the substrate of trypsin hydrolysis. The results show that protamine combines several PtNPs together to form active units, which have stronger oxidase mimicking activity than other PtNPs. In addition, the Michaelis constant of the Pro-PtNPs units is smaller than negatively charged citrate capped PtNPs, suggesting that the positively charged Pro-PtNPs units have better affinity with 3,3′,5,5′-tetramethylbenzidine (TMB), which is inconsistent with previous reports. The protamine stabilizer could be hydrolyzed in the presence of trypsin, and the Pro-PtNPs units would be decomposed and aggregated, resulting in a decrease of catalytic activity of Pro-PtNPs units. The color of the solution would be reduced according to the decrease of catalytic activity, so the catalytic activity is linearly related to UV absorbance. The linear range of trypsin detected by this new method is 0.06 μg/mL˜0.6 μg/mL, and the detection limit down to 0.03 μg/mL. Pro-PtNPs units have been successfully applied to the determination of serum trypsin and screening of inhibitors.
研究领域:
生物化学
·
纳米医学
✓ 已验证
产品关联
DOI
高影响因子
TALANTA
·
2021
·
IF 6.057
Xiaoyun Lin,Zhenmao Zhu,Dan Lin,Qiaozhen Bao,Yaoran Gao,Qicai Liu,Ailin Liu,Liqing Lin,Xinhua Lin
Nanozymes , as a new type of artificial enzyme, have recently become a research hotspot in the field of catalysis and biomedicine. However, the application of nanozyme is limited by catalytic activity changes of different substrates and low specificity. This work shows that citrate-capped platinum nanoparticles (Cit-PtNPs) exhibit stronger oxidase-like activity than other platinum nanozymes at different pH when 3-methyl-2-benzothiazolinonehydrazone hydrochloride (MBTH) and n-ethyl-n- (2-hydroxy-3-sulfopropyl)-m-toluidine sodium salt (TOOS) were used as chromogenic substrates. This phenomenon has important reference value for different nanozymes to choose chromogenic substrates in catalysis. In MBTH-TOOS chromogenic system, MBTH (-NH ) radical is first produced during the reaction through catalytic oxidation of Cit-PtNPs, which reacts with TOOS to produce a colorless compound. The blue-purple quinoid dye was produced through the dismutation of the colorless compound. The catalytic mechanism of the oxidase-like activity of Cit-PtNPs is that two-electron reduction process and four-electron reduction process are simultaneously carried out in the catalytic process. Furthermore, to solve the problem of low specificity of metal nanozymes, protamine is designed as aggregation promoter of Cit-PtNPs and the specifichydrolysis substrate of trypsin. In this work, it can achieve one-step detection of trypsin by the boosting oxidase activity of Cit-PtNPs at pH8. The catalytic activity of Cit-PtNPs is proportional to the concentration of trypsin. The linear range for trypsin is 1.0–70.0 ngmL −1 and the limit of detection is measured to be 0.6 ngmL −1 . This novel method has also been successfully applied to the detection of inhibitors and trypsin in urine samples.
研究领域:
生物化学
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医学诊断
·
催化科学
✓ 已验证
DOI
高影响因子
JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
·
2022
·
IF 5.895
Shuhua Shan,Ruopeng Yin,Jiangying Shi,Lizhen Zhang,Fengming Liu,Qinqin Qiao,Zhuoyu Li
Foxtail millet proteins and their hydrolysates have the potential to prevent atherosclerosis (AS). In our present study, a novel Bowman-Birk type major trypsin inhibitor from foxtail millet bran (FMB-BBTI) with an anti-AS effect was obtained by in vitro gastrointestinal bionic digestion. Further, the anti-AS activity of FMB-BBTI was verified by the classic apoE–/– mice model, characterized by the decreases of the inflammatory cytokines (TNF-α and IL-1β) and atherosclerotic plaque. Importantly, FMB-BBTI remodeled the structure of gut microbiota in apoE–/– mice, including the increase of Firmicutes at the phylum level, and the abundance alteration of five genera at the genus level, especially significant enrichment of Lactobacillus. Collectively, FMB-BBTI markedly restrains the AS progress, suggesting that the remodeling of gut microbiota induced by FMB-BBTI may be the critical factor for its anti-AS activity. This study indicates that FMB-BBTI may serve as a vital functional component contributing to the anti-AS potential of foxtail millet bran.
研究领域:
营养学
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心血管疾病
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微生物学
·
分子生物学
✓ 已验证
DOI
PubMed
高影响因子
ANALYTICAL CHEMISTRY
·
2013
·
IF 5.695
Jing-Min Liu,Jia-Tong Chen,Xiu-Ping Yan
The simplicity of the green-synthesized routine and the availability of surface modification of diverse bioactive molecules make noble metal nanostructures highly suitable as multifunctional biomaterials for biological and biomedical application. Here, we report the preparation of trypsin stabilized gold nanoclusters (try-AuNCs) with near-infrared fluorescence for biosensing heparin based on surface plasmon enhanced energy transfer (SPEET) and folic acid (FA) modified try-AuNCs for in vivo cancer bioimaging. The SPEET/try-AuNCs fluorescence biosensor was designed via heparin mediated energy transfer between try-AuNCs and cysteamine modified gold nanoparticles (cyst-AuNPs). The developed SPEET/try-AuNCs fluorescence biosensor allowed sensitive and selective detection of heparin with a linear range of 0.1–4.0 μg mL–1 and a detection limit (3s) of 0.05 μg mL–1. The relative standard deviation for eleven replicate detections of 2.5 μg mL–1 heparin was 1.1%, and the recoveries of the spiked heparin in human serum samples ranged from 97% to 100%. In addition, folic acid was immobilized on the surface of try-AuNCs to ameliorate the specific affinity of AuNCs for tumors, and the near-infrared fluorescent FA-try-AuNCs were applied for in vivo cancer imaging of high folate receptor (FR) expressing Hela tumor. In vivo study of the dynamic behavior and targeting ability of FA-try-AuNCs probe to Hela tumor bearing mice and normal nude mice validated the high specific affinity of FA-try-AuNCs probe to FR positive tumors. The results show that the prepared try-AuNCs have great potential as multifunctional biomaterials for biosensing biomolecules with SPEET mode and in vivo cancer imaging with high targeting ability.
研究领域:
生物化学
·
纳米医学
·
分析化学
·
肿瘤学
✓ 已验证
DOI
高影响因子
TALANTA
·
2018
·
IF 4.244
Shiyu Zhang,Can Chen,Xiaofei Qin,Qianchen Zhang,Jinhua Liu,Jixin Zhu,Yongqian Gao,Lin Li,Wei Huang
Trypsin, as one of important proteases, is specific for catalyzing the hydrolysis of peptide and ester bonds containing lysine and arginine residues at the C-terminus. The level of trypsin in biological fluids can serve as a reliable and specific diagnostic biomarker for pancreatic function and its pathological changes. Herein, we demonstrate the application of phosphorescent Cu NCs for trypsin detection for the first time depending on the electron transfer between Cu NCs and cyt c. Cyt c and Cu NCs were selected as the quencher and the fluorophore, respectively. Cu NCs could bind to the positively charged cyt c through electrostatic and hydrophobic interactions, and the phosphorescence of Cu NCs was efficiently quenched by the metal-containing heme of cyt c. In the presence of trypsin, cyt c was digested, thus phosphorescence of Cu NCs remained. Therefore, a new and continuous phosphorescence assay for the detection of trypsin activity and its inhibitor screening was established. The plot of relative fluorescence versus trypsin concentration obtains a good linear detection range from 0 to 20 ng/mL (R 2 = 0.9657), and a detection limit of 2 ng/mL, which is much lower than 20 ng/mL of the sensor in buffer solution because of urine amplifying the phosphorescence signal of Cu NCs based on the FRET strategy. This assay still has been successfully applied to trypsin inhibitor screening, demonstrating its potential application in drug discovery.
研究领域:
生物化学
·
医学诊断
·
药物发现
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ANALYTICA CHIMICA ACTA
·
2018
·
IF 5.123
Yanyu Lin,Rongkai Shen,Nannan Liu,Huan Yi,Hong Dai,Jianhua Lin
Here, a simple electrochemical biosensor was proposed based on the specific recognition between trypsin and peptide. Initially, NiCo 2 O 4 -PAMAM nanocomposite was casted on the bare electrode to achieve the electrochemical signal amplification in 0.1 mM [Ru(NH 3 ) 6 ] 3+ solution owing to the great electronic conductivity and high electrochemical activity induced by the special structure of NiCo 2 O 4 nanosheets (Ni 3+ cations in octachedral sites of the Co 3 O 4 ). Subsequently, a declined electrochemical signal was obtained when g-C 3 N 4 labeled peptide composites were anchored on the electrode. However, after trypsin was added into solution and incubated with the biosensor, the electrochemical signal was re-promoted. Therefore, the as-synthesized biosensor could realize the sensitive detection of trypsin by virtue of the specific recognition between trypsin and peptide. As a result, the developed peptide-based exhibited a linear range from 10 −10 to 10 −4 mg mL −1 with an ultralow detection limit of 10 −10 mg mL −1 , providing sensitive analytical performance and acceptable application potential in clinical test and disease diagnosis due to its high stability, excellent selectivity , acceptable reproducibility and accurate signal output.
研究领域:
生物传感技术
·
医学诊断
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Food Biophysics
·
2016
·Vol. 12
·期 1
·78-87
·
IF 1.605
Wu Zhibing,Shen Liangliang,Han Qingguo,Lu Jun,Tang Haifeng,Xu Xu,Xu Hong,Huang Fengwen,Xie Jiangfeng,He Zhendan,Zeng Zheling,Hu Zhangli
Ligupurpuroside A is a glycoside extracted from Ku-Ding tea. As extracts from Ku-Ding tea exhibit anti-inflammatory property, we hypothesize that Ligupurpuroside A may be an active compound which inhibits trypsin activity during the anti-inflammatory process. The mechanism and nature of inhibition of trypsin by Ligupurpuroside A have been studied by multi-spectroscopic method, enzyme-activity assay and molecular docking. Enzyme activity assay reveals that Ligupurpuroside A significantly inhibits the activity of trypsin through a competitive manner with an IC 50 value of 3.08 × 10 −3 mol L −1 . Fluorescence titration together with thermodynamic analysis indicate that a Ligupurpuroside A-trypsin complex is formed, and that hydrophobic force and hydrogen bonding are the main forces stabilizing the complex. UV-vis absorption, synchronous fluorescence and circular dichroism spectra show that the interaction between Ligupurpuroside A and trypsin induces conformational changes of trypsin with a decrease in the contents of α-helix and β-sheet. Finally, molecular docking further suggests that Ligupurpuroside A molecule binds within the active pocket of trypsin via hydrophobic force and hydrogen bond. Results from this study of the interaction of trypsin with its natural inhibitor should be useful to minimize the antinutritional effects and make full use of tea extracts in the food industry, and be also helpful to the design of the drugs for the diseases related to overexpression of trypsin.
研究领域:
生物化学
·
药物设计
·
食品科学
✓ 已验证
DOI
高影响因子
ANALYTICA CHIMICA ACTA
·
2020
·
IF 5.977
Wei Zhao,Bing Li,Sheng Xu,Ye Zhu,Xiaoya Liu
A high-performance molecularly imprinted sensing platform inspired by natural recognition mechanisms was fabricated to detect protein by employing a linear electro-polymerizable molecularly imprinted polymer as macromonomer. This was achieved via the combination of a biosensor fabrication with a self-assembly imprinting technique without the use of chemical labels. An amphipathic electroactive copolymer was designed as macro-monomer to maintain structural integrity of the protein template via self-assembly, resulting in generation of a 3D construction around the protein molecule to form imprinted sites. Electro-polymerization was utilized not only to anchor imprinted sites but also to enhance electron transfer . The adaptable sensing platform was based on a strengthened recognition reaction between the MIP layer and template protein after the generation of an electroactive network. Bovine serum albumin (BSA) and trypsin were used as model proteins to investigate the method’s generality, which gave broad detection ranges of 10 −14 –10 −5 mg mL −1 for BSA and 10 −13 –10 −8 mg mL −1 for trypsin. These results indicate that the proposed fabrication offers an effective and versatile strategy for protein recognition.
研究领域:
生物化学
·
分析化学
✓ 已验证
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）