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 opt...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%.展开更多
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 microcalorimet...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 condition.The 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.展开更多
Homeostasis creates self-organized synchrony of the body’s reactions, and despite the energetically open system with intensive external and internal interactions, it is robustly stable. Importantly the self-organized...Homeostasis creates self-organized synchrony of the body’s reactions, and despite the energetically open system with intensive external and internal interactions, it is robustly stable. Importantly the self-organized system has scaling behaviors in its allometry, internal structures, and dynamic processes. The system works stochastically. Deterministic reductionism has validity only by the great average of the probabilistic processes. The system’s dynamics have a characteristic distribution of signals, which may be characterized by their frequency distribution, creating a particular “noise” 1/<em>f </em>of the power density. The stochastic processes produce resonances pumped by various noise spectra. The chemical processes are mostly driven by enzymatic processes, which also have noise-dependent resonant optimizing. The resonance frequencies are as many as many enzymatic reactions exist in the target.展开更多
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 thixot...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.展开更多
Enzymes containing 3′→5′exonuclease activities play an important role in various key cellular and physiological processes.The development of fluorescence biosensor is an efficient method to detecting enzyme activit...Enzymes containing 3′→5′exonuclease activities play an important role in various key cellular and physiological processes.The development of fluorescence biosensor is an efficient method to detecting enzyme activity.Herein,a fluorescence resonance energy transfer(FRET)“on”and“off”strategy for detecting exonuclease III(Exo III)activity has been developed.We 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 PMI-O7.Upon the addition of Exo III,the dsDNA will be digested and the FAM fluorophore will be released,resulting in the fluorescence recovery of FAM.This method provides a simple and sensitive biosensor platform with a low detection limit of 0.077 U/mL for Exo III.Importantly,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.展开更多
文摘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%.
文摘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 condition.The 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.
文摘Homeostasis creates self-organized synchrony of the body’s reactions, and despite the energetically open system with intensive external and internal interactions, it is robustly stable. Importantly the self-organized system has scaling behaviors in its allometry, internal structures, and dynamic processes. The system works stochastically. Deterministic reductionism has validity only by the great average of the probabilistic processes. The system’s dynamics have a characteristic distribution of signals, which may be characterized by their frequency distribution, creating a particular “noise” 1/<em>f </em>of the power density. The stochastic processes produce resonances pumped by various noise spectra. The chemical processes are mostly driven by enzymatic processes, which also have noise-dependent resonant optimizing. The resonance frequencies are as many as many enzymatic reactions exist in the target.
文摘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.
基金supported by the Natural Science Foundation of Guangdong Province,China (No.2014A030313194)the Science and Technology Program of Guangzhou,China (No.201804010017)+1 种基金the Science and Technology Program of Guangdong Province,China (No.2017A050506021)the National Natural Science Foundation of China (No.21374137).
文摘Enzymes containing 3′→5′exonuclease activities play an important role in various key cellular and physiological processes.The development of fluorescence biosensor is an efficient method to detecting enzyme activity.Herein,a fluorescence resonance energy transfer(FRET)“on”and“off”strategy for detecting exonuclease III(Exo III)activity has been developed.We 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 PMI-O7.Upon the addition of Exo III,the dsDNA will be digested and the FAM fluorophore will be released,resulting in the fluorescence recovery of FAM.This method provides a simple and sensitive biosensor platform with a low detection limit of 0.077 U/mL for Exo III.Importantly,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.