JOURNAL OF PHYSICAL CHEMISTRY B
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2025
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IF 2.9
Lei Wang,Zhen-Zhen Li,Gong-Ji Chen,Mi-Zhuan Li,Yan Cheng,Zhong-Xiu Chen
The activity of lipase was inhibited or promoted by different macromolecular colloids, but the underlined general rules were not clear. In this paper, lipase activity was systematically analyzed in different macromolecular media. The detailed factors that affect the enzyme activity were extracted for quantification. Three functions, including viscosity, the crowding effect, and soft interactions, were established to describe the macromolecular medium effect. The medium parameter based on the Huggins constant and Kramer constant was able to characterize the quality of the macromolecular media. A multivariate nonlinear regression model was proposed for the correlation or prediction between three groups of factors and enzyme activity, and a crowding enzyme factor CCef was proposed. This study pioneered the qualification and prediction of the multiple factors that affect the enzyme activity in complex media. It is also significant for scientifically predicting the efficacy of functional macromolecules related to healthy food and the formulation of dietary fibers.
研究领域:
生物化学
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食品科学
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DOI
PubMed
高影响因子
JOURNAL OF CHROMATOGRAPHY A
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2020
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IF 4.049
Jian Yang,Xue Zhang,Yasen Mijiti,Yakun Sun,Man Jia,Zhaosheng Liu,Yanping Huang,Haji Akber Aisa
The topic in the present paper is to prepare molecularly imprinted polymer (MIP) using the template molecule with low purity. For the first time, a surrounding of macromolecular crowding was established to promote the formation of the complex of the template with functional monomer efficiently thus highly pure template molecule was unnecessary. In this study, the MIP monolith was synthesized using low purity lactucopicrin as template in place of highly pure one, and polystyrene was used as macromolecular crowding agent. 4-Vinylpyridine and ethyleneglycol dimethacrylate were used as functional monomer and crosslinker, respectively. Polymerization parameters, including the ratio of functional monomer/template, various template concentrations, and PS concentration on the affinity of the resulting MIP were systematically investigated. For the lactucopicrin MIP made with the purity of lactucopicrin of 92%, the imprinting factor can be up to 2.2. The resulting MIP was filled in solid phase extraction (SPE) cartridge to purify lactucopicrin from the crude extract of Cichorium glandulosum Boiss. et Huet. After two cycles of MIP SPE for the crude extract, the highest recovery and purity of lactucopicrin was 64.8% and 97.8%, respectively. The results indicated that the use of macromolecular crowding agent is an effective method for improving the performance of the MIP prepared with the template of low purity, particularly valuable to the cases in which the highly pure target molecule is hard to be obtained.
研究领域:
化学
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生物学
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PubMed
高影响因子
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
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2025
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IF 8.5
Li Wen,Jinxia Zheng,Zhijie Ke,Jian Dong
Enzymes catalyze cascade reactions in a crowded cellular environment where as much as half of cell volume is occupied by various macromolecules. Nonspecific interaction between enzymes and crowders and excluded volume of the crowders can superimpose on each other and complicate catalytic activity of the enzymes. This study investigates the interaction between a β-galactosidase (β-Gal) and glycosylated acrylamide polymer (P(Glc-β-EAAm)) and unravels the macromolecular crowding effect of the glycopolymer on enzymatic cascade catalysis consisting of β-Gal, glucose oxidase and hydrogen peroxidase. Binding of the glycopolymer induced conformational alterations in β-Gal and gave rise to static fluorescence quenching and stable complex formation with β-Gal via nonspecific interaction. Fluorescence resonance energy transfer assays further demonstrated a compact association between β-Gal and glycopolymer crowders, with binding affinity correlating with the molecular weight of glycopolymer. The reduction of the apparent kinetic constants of the catalysis with the glycopolymer size showed the role of the multivalent effect in enzyme-substrate interactions. The kinetics also depended on the chain overlapping conditions of the crowders. Therefore, the macromolecular crowding effect on the cascade reaction is jointly associated with the crowder's multivalent effect, chain overlapping conditions of the crowders, in addition to the volume exclusion effect of the crowders.
研究领域:
生物化学
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酶学
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高分子科学
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PubMed
高影响因子
JOURNAL OF SEPARATION SCIENCE
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2016
·Vol. 39
·期 10
·1963-1970
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IF 2.741
Guang-Ying Sun,Chao Wang,Yu-Qin Luo,Yong-Xin Zhao,Jian Yang,Zhao-Sheng Liu,Haji Akber Aisa
The combination of molecular crowding and virtual imprinting was employed to develop a cost-effective method to prepare molecularly imprinted polymers. By using linear polymer polystyrene as a macromolecular crowding agent, an imprinted polymer recognizable to punicalagin had been successfully synthesized with punicalin as the dummy template. The resulting punicalin-imprinted polymer presented a remarkable selectivity to punicalagin with an imprinting factor of 3.17 even at extremely low consumption of the template (template/monomer ratio of 1:782). In contrast, the imprinted polymer synthesized without crowding agent, did not show any imprinting effect at so low template amount. The imprinted polymers made by combination of molecular crowding and virtual imprinting can be utilized for the fast separation of punicalagin from pomegranate husk extract after optimizing the protocol of solid-phase extraction with the recovery of 85.3 ± 1.2%.
研究领域:
分析化学
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天然产物分离纯化
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高影响因子
MACROMOLECULES
·
2024
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IF 5.1
Jianing Zhou,Tao Zheng,Huanli Qi,Yiren Wang,Mingming Ding,Lianwei Li
By using a series of mixed solutions composed of styrene oligomers (PSN, 10 < N < 550) and toluene, this work explores how the macromolecule crowding effects, including viscosity effect and conformational compression, regulates the flow-driven translocation, i.e., compression-induced fractionation (CIF), of polystyrene long chains (PS-1100k, 1.10 × 106 g/mol) through nanochannels (average pore radius r0 ≈ 10 nm). The correlation between the macroscopic critical flow rate (Qc) and apparent viscosity (ηapp) has been tested. Specifically, we have found the following: (1) ηapp of PSN–toluene mixed solutions is found to be easily regulated in a broad range (0.52 ≤ ηapp ≤ 5.02 mPa·s) by the oligomer strategy, which is beyond the window achieved by the small-molecule solvent system; (2) the translocation experiments in mixed solutions support the relation of Qc ∼ 1/ηapp predicted by de Gennes theory in the range of 0.52 mPa·s ≤ ηapp ≤ 1.53 mPa·s, but a deviation is observed when 1.53 < ηapp ≤ 5.02 mPa·s, implying the potential influence from the conformational compression of chains for CIF; (3) through a coarse-grained simulation on the blend system composed of a long chain (Nl = 100) and oligomer short chains (1 ≤ Ns ≤ 20) with varied volume fraction (φs) from 0.1 to 0.4, the simulation result shows that the degree of compression of the long chain increases with Ns and φs of oligomer short chains. Overall, the present study has preliminarily explored how the macromolecule crowding effects (viscosity effect and conformational compression) play the dominant role in regulating translocation behavior during the CIF process, which paves the foundation for understanding the transmembrane transport of biological macromolecules in the natural crowding cell environments.
研究领域:
高分子科学
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生物物理学
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计算模拟
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高影响因子
FOOD CHEMISTRY
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2023
·
IF 8.8
Yu-Long Sun,Yi-Fan Tang,Lei Wang,Mi-Zhuan Li,Zhong-Xiu Chen
The macromolecular crowding effects of polysaccharides can alter the activity of digestive enzymes; however, whether protein crowding affects the digestive properties of starch remains unknown. Herein, the interaction of sodium caseinate (NaCas) with starch and pig pancreas α-amylase (PPA) and their effects on enzyme activity and starch digestion were studied. NaCas delayed gelatinization and reduced the leaching amount of amylose and increased the relative content of easily digestible starch. The ratio of the ordered structure (α-helix and β-sheet) to disordered structure (β-turns) of PPA increased with NaCas concentration, indicating that NaCas maintained the conformational stability of the enzyme and thereby accelerated the rate of enzymatic hydrolysis. This study demonstrates the detailed mechanism of NaCas-induced enhancement of starch digestibility and suggests a nonnegligible macromolecular crowding effect should be considered when evaluating the function of food macromolecules.
研究领域:
食品科学
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生物化学
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营养学
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PubMed
高影响因子
ANALYTICAL AND BIOANALYTICAL CHEMISTRY
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2015
·Vol. 407
·期 24
·7401-7412
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IF 3.436
Sun Guang-Ying,Zhong Dan-Dan,Li Xiang-Jie,Luo Yu-Qing,Ba Hang,Liu Zhao-Sheng,Aisa Haji Akber
One of the main challenges in the preparation of molecularly imprinted polymers (MIPs) is the substantial initial amount of template needed because of the requirement of high load capacities for most applications. A new strategy of macromolecular crowding was suggested to solve this problem by reducing the amount of template in the polymerization recipe. In a ternary porogenic system of polystyrene (PS) (crowding agent), tetrahydrofuran, and toluene, an imprinted monolithic column with high porosity and good permeability was synthesized using a mixture of ellagic acid (template), acrylamide, and ethylene glycol dimethacrylate. The effect of polymerization factors, including monomer–template molar ratio and the molecular weight and concentration of PS, on the imprinting effect of the resulting MIP monoliths was systematically investigated. At a high ratio of monomer–template (120:1), the greatest imprinting factor of 32.4 was obtained on the MIP monolith with the aid of macromolecular crowding agent. The PS-based imprinted monolith had imprinting even at the extremely high ratio of functional monomer to template of 1510:1. Furthermore, an off-line solid-phase extraction based on the ground MIP was conducted, and the purification recovery of ellagic acid from pomegranate-rind extract was up to 80 %. In conclusion, this approach based on macromolecular crowding is simple, and is especially valuable for those applications of MIP preparation for which a rare template is used.
研究领域:
分析化学
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材料科学
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PubMed
高影响因子
Nanoscale
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2023
·
IF 6.7
Jie Dai,Zhiyi Peng,Shuwei Shen,Binbin Huang,Lili Ren,Jia Liu,Chia Hung Chen,Guoguang Chen
The dysfunction of intracellular proteins is frequently associated with various diseases, such as cancer. The exogenous proteins in cells are usually assembled with specific configurations due to physiological confinement/crowding to exhibit novel features in protein structure, folding or conformational stability, distinguished with their behaviors in buffer solutions. Here, we synthesized exogenous proteins in a confined/crowded condition, to explore protein activity within the cells. The findings suggested that the confinement and crowding effects on protein activity are heterogeneous; they showed an inhibitory consequence on HRP by decreasing Km (from ~9.5- and ~21.7-fold) and Vmax (from ~6.8- and ~20.2-fold) lower than that of dilute solutions. Interestingly, the consequences on Cyt C seem more complicated, and the crowding exerts a positive effect by increasing Km ~3.6-fold and Vmax ~1.5-fold higher than that of dilute solutions; however, the confinement takes a negative consequence by decreasing Km ~2.0 and Vmax ~8.3 times. Additionally, in contrast to traditional nanoparticles-based confinement models, we synthesized a biodegradable nanoparticle to mimic the confined space, and the biggest advantage of this novel model is that the particles can be degraded and thus it can provide more intuitive observations of the target protein properties under the confinement and after release. Furthermore, we also evaluated protein activity in different cellular environments, indicating the exogenous protein activity was closely related to the crowdedness of cellular environments, and the inhibition of protein activity in MDA-MB-231 cancer cells was more obvious than HEK293 normal cells. Finally, SAXS analysis revealed the correlation between the protein conformation and the different environments. Our work will provide a unique way for precisely assessing whether the target cellular environments are native matrix in which specific exogenous protein drugs delivered to function or whether they display a therapeutic role, which is of great significance for screening and development of new drugs.
研究领域:
生物物理学
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细胞生物学
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药学
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纳米技术
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高影响因子
BIOCHEMICAL ENGINEERING JOURNAL
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2020
·
IF 3.475
Nan Jiang,Xuanwei Ding,Yuan Lu
Since the cell-free protein synthesis system is not limited by the cell growth, all the substrates are used to produce the protein of interest, and the reaction environment can be flexibly controlled. All the advantages allow it to synthesize toxic proteins, membrane proteins, and unnatural proteins that are difficult to make in vivo . However, one typical reason why the cell-free system has not been widely accepted as a practical alternative, is its expression efficiency problem. The Escherichia coli -based system was chosen in this study, and the model protein deGFP was expressed to explore a more efficient cell-free system. The results showed that Mg 2+ with a concentration of 15 mM in the cell-free system with BL21 Star (DE3) as the extract could better synthesize protein. The smaller the vectors, the lighter the burden, the higher the protein synthesis. Simulating the crowding effect in the cell does not improve the protein expression efficiency of the optimized cell-free protein synthesis system. Based on the optimized system, the cell-free fundamental research platform, primary screening platform, and portable biomolecular synthesis platform were established. This study provides a robust cell-free protein synthesis toolbox with easy extract preparation and high protein yield. It also enables more researchers to reap the benefits from the cell-free biosynthesis platform.
研究领域:
生物技术
·
蛋白质工程
·
合成生物学
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高影响因子
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2023
·
IF 8.2
Siyuan Xu,Jie Wang,Jian Dong
Macromolecular crowding can change kinetics of enzyme catalysis . How interaction between enzymes and neighboring macromolecules contributes to the crowding effect on enzyme catalysis has not been quantitatively revealed. In this study, crowding effects of dextran and poly(ethylene glycol) (PEG) on glucose oxidase (GOx) are studied. Fluorescence resonance energy transfer experiments show the high transfer efficiency and stable interaction between the dextran and GOx. Further fluorescence quenching analysis also proves that the association of the dextran-GOx pair can become stronger than that of the PEG-GOx pair. Dextrans with concentrations above or below their chain overlap concentrations (c*) reduce Michaelis constants (K m ) of GOx catalysis by 90 % or 45 %, respectively, through volume exclusion mechanism, and in the meantime elevate the enzymatic efficiency (k cat /K m ) by 8-fold or by 3-fold, respectively, which is more dramatic than that found in other enzymes before. Strong association between the enzyme and the dextran results in slow turnover rates (k cat ). Intermediate crowding with weak to moderate affinity to the enzyme below the c* can tune the k cat higher than in the free state. Catalysis under crowded conditions is a joint effect of the enzyme-crowder nonspecific interaction, volume exclusion and overlap condition of the crowders.
研究领域:
生物化学
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分子生物学
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酶学
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DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）