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enzymatic reaction of ethanol and oleic acid by lipase and lignin peroxidase in rhamnolipid(RL) reversed micelles

Journal of Central South University 2015年第8期22卷 2936-2944页

作者：包珊袁兴中彭馨曾光明武海鹏王侯刘欢马玉洁崔凯龙吴秀莲 College of Environmental Science and Engineering Hunan University Key Laboratory of Environmental Biology and Pollution Control of Ministry of Education (Hunan University)

An environment friendly bio-surfactant of rhamnolipid(RL) was used as a solvent. The enzymatic reaction of oleic acid catalyzed by lipase and lignin peroxidase(lip) was evaluated. The optimum conditions of enzymatic reaction catalyzed by lipase(lip) were water to amphiphile molar ratio of 30(20), RL of 60(60) critical micelle concentration(CMC), pH of 7.0(3.0) and temperature of 40(30) °C, respectively. The change of enzyme conformation indicates that, for catalytic of lipase, water content is the most important factor of the enzymatic reaction of oleic acid, and p H for lip. With individual optimum conditions, the enzymatic efficiency of oleic acid catalyzed by lipase is higher than that by lip. In the presence of ethanol, the enzymatic reaction of oleic acid catalyzed by lipase suits Ping-Pong Bi-Bi mechanism. As an alternative to chemical reversed micelles, the RL reversed micelles are promising methods to enzymatic reaction of oleic acid.

关键词： lipase lip enzymatic reaction rhamnolipid reversed micelles oleic acid

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Self-assembled Nanosheets of Perylene Monoamide Derivative as Sensitive Fluorescent Biosensor for Exonuclease Ⅲ Activity

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Chemical Research in Chinese Universities 2022年第6期38卷 1497-1503页

作者： QIN Yang YANG Yunhan HE Ran ZHOU Laicheng ZHANG Ling PCFM Lab and GDHPRC Lab School of ChemistrySun Yat-sen UniversityGuangzhou510275P.R.China

Enzymes containing 3′→5′exonuclease activities play an important role in various key cellular and physiological *** development of fluorescence biosensor is an efficient method to detecting enzyme ***,a fluorescence resonance energy transfer(FRET)“on”and“off”strategy for detecting exonuclease III(Exo III)activity has been *** report here that the double-stranded DNA(dsDNA)enables to bind tightly to self-assembled nanosheets of cationic perylene monoimide derivative(PMI-O7)through electrostatic interaction,and the 6-carboxyfluorescein(FAM)-modified dsDNA could be efficiently quenched via FRET between FAM and *** the addition of Exo III,the dsDNA will be digested and the FAM fluorophore will be released,resulting in the fluorescence recovery of *** method provides a simple and sensitive biosensor platform with a low detection limit of 0.077 U/mL for Exo ***,this method exhibits similar and calibration curves for the detection of Exo III in both buffer and fetal bovine serum samples,indicating that this platform has potential to detect Exo III activity in complex samples.

关键词： Nanosheet Fluorescence biosensor enzymatic reaction

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Precursor-involved and Conversion Rate-controlled Self-assembly of a ＇Super Gelator＇ in Thixotropic Hydrogels for Drug Delivery

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Chinese Journal of Chemistry 2012年第8期30卷 1781-1787页

作者：区彩文王怀民杨志谋陈敏生 Guangzhou Medical University GuangzhouGuangdong 510182China State Key Laboratory of Medicinal Chemical Biology and College of Life Sciences Nankai UniversityTianjin 300071China

enzymatic hydrogelation is a totally different process to the heating-cooling gelation process, in which the pre- cursors of the gelators can be involved during the formation of self-assembled structures. Using thixotropic hy- drogels formed by a super gelator as our studied system, we demonstrated that the enzyme concentration/conversion rate of enzymatic reaction had a strong influence on the morphology of resulting self-assembled nanostructures and the property of resulting hydrogels. The principle demonstrated in this study not only helps to understand and elucidate the phenomenon of self-assembly triggered by enzymes in biological systems, but also offers a unique methodology to control the morphology of self-assembled structures for specific applications such as controlled drug re- lease.

关键词： self-assembly hydrogel enzymatic reaction

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enzymatic Determination of Glucose by Optical-Fiber Sensor Sequential Injection Renewable Surface Spectrophotometry

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Chemical Research in Chinese Universities 2006年第3期22卷 287-291页

作者： WANG Jian-ya FANG Zhao-lun Research Center for Analytical Sciences Northeastern University Shenyang 110006 P. R. China School of Petrochemical Engineering Shenyang University of Technology Shenyang 111003 P. R. China

On the basis of oxidative decoloration of bromopyrogallol red （BPR） with H2O2, catalyzed by horseradish peroxidase（ HRP）, and the sequential injection renewable surface technique（ SI-RST）, a highly sensitive optical-fiber sensor spectrophotometric method for the enzymatic determination of hydrogen peroxide was proposed. By coupling with a glucose oxidase（GOD）-catalyzed reaction, the method was used to determine glucose in human serum. The considerations in system and flow cell design, and factors that influence the determination performance are discussed. With 100μL of sample loaded and 0. 6 mg of bead trapped, the linear response range from 5.0 × 10^-8 to 5.2 × 10^-6 mol/L BPR with a detection limit（3σ） of 2. 5 ×10 ^-8 mol/L BPR, and a precision of 1.1% RSD（ n = 11 ） and a throughput of a 80 samples per hour can be achieved. Under the conditions of a 8. 7 × 10^ -6 mol/L BPR substrate, 0. 04 unit/mL HRP, 600 s reaction time and a reaction temperature of 37℃, the linear response range for H2O2 was from 5.0 × 10^-8 to 7.0 × 10^-6 mol/L with a detection limit（3σ） of 1.0 × 10^-8 mol/L and a precision of 3.7% RSD （ n = 11 ）. The linear response range by coupling with a GOD-catalyzed reaction was from 1.0 × 10^-7 to 1.0 × 10^-5 mol/L. The method was directly applied to determine glucose in human serum. Glucose contents obtained by the proposed procedure were compared with those obtained by using the phenol-4-AAP method, the error was found to be less than 3%.

关键词： Sequential injection renewable surface Optical-fiber sensor enzymatic reaction Glucose

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DFT Study on the Roles of Calcium and Its Coordination Variation Play in the Mechanism of Diisopropyl Fluorophosphatase

DFT Study on the Roles of Calcium and Its Coordination Varia...

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中国化学会第30届学术年会-第十九分会：化学中的量子与经典动力学

作者： Ling Yang W.Tian R.-Z.Liao Institute of Theoretical and Simulation Chemistry School of Chemistry and Chemical Engineering Harbin Institute of Technology School of Chemistry and Chemical Engineering Huazhong University of Science and Technology

Catalytic mechanism of diisopropyl fluorophosphatase from Loligo vulgaris is investigated using the hybrid density functional theory method B3LYP with a large quantum chemical model of the active site. For the first step, both Asp229 and an activated water molecule are capable of proceeding in-line attack on the substrate with the associated barriers 14.8 and 6.0 kcal/mol, respectively. Asp229 plays a dual role during the two reaction processes as either a nucleophile or a general base to activate HO. From the phosphoenzyme intermediate with hexa-coordinated Ca, the uncoordinated Glu21 activated an additional HO to attack the carbon center of Asp229 and make the phosphate release. Asn120 and Asn175 promote the elimination of the fluoride via donating strong hydrogen bonds. Coordination variation of calcium plays important role of the enzymatic reaction to occur. The calculated detailed reaction mechanisms will promote the structure-based protein engineering to modify hydrolysis rates and substrate specific.

关键词： enzymatic reaction Hydrolysis Mechanism Density functional calculations

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STUDIES OF THE reaction BETWEEN LACCASE AND p-PHENYLENEDIAMIME BY MICROCALORIMETRY

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Wuhan University Journal of Natural Sciences 1998年第1期3卷 107-107页

作者： Xie Xiuyin Yan Chengnong Wu Dingquan Qu Shongsheng Du Yumin Wuhan University Department of Chemistry Wuhan China (GRID:grid.49470.3e) (ISNI:***) Wuhan University Department of Environment Science Wuhan China (GRID:grid.49470.3e) (ISNI:***)

The molar reation enthalpy,the Michaelis constant and the observed rate constant of the reaction between the Rhus vernicifera laccase and p-phenylenediamine have been determined at 298. 15 K by LKB-2107 microcalorimetry system in 0.1 mol/L phosphate salt buffer (pH7. 4) to be △rHm=-136.36±0. 36kJ/mol, Km= 5. 58×10-3 mol/L and k1 =8. 63×10-3s-1, respectively. The catalyst activity of laccase withp-phenylenediamine as substrate has been determined to be EA=0. 045 IU in the experimental *** observed activation energy of non-enzymic step of the reaction, the Gibbs binding energy of the combination process of laccase and substrate have been also calculated. The physical significance of the determined parameters were discussed for different step of the reaction.

关键词： microcalorimetry rhus vernicifera laccase p-phenylenediamine enzymatic reaction

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