Non-aqueous phase enzymatic catalysis technology has been widely ap- plied in the area of food additives production. This paper reviewed the types of re- action medium of non-aqueous phase enzymatic catalysis reaction...Non-aqueous phase enzymatic catalysis technology has been widely ap- plied in the area of food additives production. This paper reviewed the types of re- action medium of non-aqueous phase enzymatic catalysis reaction, introduced the application of non-aqueous phase enzymatic catalysis technology in catalysis of L-ascorbic (isoascorbic) acid esters, short-chain acid esters, sugar esters, vitamin A esters, vi- tamin E esters, and other food additives, and finally predicted the prospects of non- aqueous phase enzymatic catalysis technology.展开更多
Biodiesel is an excellent option for reducing dependence on fossil fuels with environmental advantages by reducing hazardous emissions. The enzymatic transesterification has attracted the attention of researchers in t...Biodiesel is an excellent option for reducing dependence on fossil fuels with environmental advantages by reducing hazardous emissions. The enzymatic transesterification has attracted the attention of researchers in the last decade and the advantages of enzymatic catalysis show that the production of biodiesel by this route has good potential, mainly because it is friendly environment. For biodiesel, production process by enzyme catalysis is chosen the response surface methodology. It is an experimental strategy to find the best operating conditions oftransesterification reaction to improve the biodiesel quality. The Process has three variables: temperature, molar ratio oil-alcohol and catalyst quantity. The process was monitored by GC-FID (gas chromatography with flame ionization detector). The yield of the transesterification reaction by enzymatic catalysis decreases with increasing temperature, and may be due to inactivation of the enzyme by denaturation at temperatures above 50 ℃. The second-order design used was the "CDC (central design composition)" which produced a maximum yield of 95.5% in the transesterification reaction by enzymatic catalysis obtained at a temperature of 45 ℃, molar ratio methanol:oil of 8:1 and a catalyst loading of 8% wt.展开更多
Currently, biodiesel is presented as one of the best alternatives for gradually replacing the use of fossil fuels, but it has some factors that make it economically impractical if it does not have a government support...Currently, biodiesel is presented as one of the best alternatives for gradually replacing the use of fossil fuels, but it has some factors that make it economically impractical if it does not have a government support. For this reason, research efforts focused on this area have been responsible for optimizing the process of biodiesel production by different catalytic routes to achieve greater efficiency at a lower cost. In this case, the biggest problem has been the high cost generated by an investigation, which in many occasions is the main factor to decide if an investigation could be carried out. Trying to reduce these costs, in the current study, we are using a technique of glycerol quantification by volumetric methods and comparing obtained results with the chromatographic method, which is conventionally used and comparatively much more expensive. Biodiesel employee was obtained by an enzymatic catalysis process varying one of three process variables:oil:alcohol molar ratio, temperature and proportion of catalyst. The numerical differences obtained between the two quantification methods generated relative errors lower than 10%, resulting in some occasions lower than 1%. By gas chromatography analysis the best yield was obtained at the same conditions of the volumetric method, a temperature of 45 ℃, an oil:alcohol ratio 1:4 and 8 wt.% of catalyst, but a yield of 95.5% and 97.1%, respectively. Due to the high precision of gas chromatography, this method is used to carry out a surface response analysis obtaining as ideal operating conditions a temperature of 43.5 ℃, 8.9 wt.%. of catalyst and an oil:alcohol ratio 1:4.展开更多
Ionic liquids have negligibly low vapor pressure, high stability and polarity. They are regarded as green solvents. Enzymes, especially lipases, as well as whole-cell of microbe, are catalytically active in ionic liqu...Ionic liquids have negligibly low vapor pressure, high stability and polarity. They are regarded as green solvents. Enzymes, especially lipases, as well as whole-cell of microbe, are catalytically active in ionic liquids or aqueous-ionic liquid biphasic systems. Up to date, there have been many reports on enzyme-exhibited features and enzyme-mediated reactions in ionic liquids. In many cases, remarkable results with respect to yield, catalytic activity, stability and (enantio-, regio-) selectivity were obtained in ionic liquids in comparison with those observed in conventional media. Accordingly, ionic liquids provide new possibilities for the application of new type of solvent in biocatalytic reactions.展开更多
hoton emission properties of polyphenylphenol (PPP) synthesized in the pres-ence of a newly-found enzymatic catalyst are reported. The photoluminescence peakexcited by the light at 350 nm is at about 370-420 nm. The a...hoton emission properties of polyphenylphenol (PPP) synthesized in the pres-ence of a newly-found enzymatic catalyst are reported. The photoluminescence peakexcited by the light at 350 nm is at about 370-420 nm. The absorption band edgesand photon emitting peaks of the polymer were found dependent on the conjugatedlengths of the polymer. In the transient luminescence measurement the lifetime ofPL decay was determined to be 2. 0 ns which is supposed as the evidence of polaronexcitation recombination.展开更多
An electrochemical immunosensor was developed for sensitive assay ofE. coli in urban sludge, in which electron mediator-mediated enzymatic catalysis and gold nanoparticles(AuNPs) were utilized for signal amplificati...An electrochemical immunosensor was developed for sensitive assay ofE. coli in urban sludge, in which electron mediator-mediated enzymatic catalysis and gold nanoparticles(AuNPs) were utilized for signal amplification. The immnuosensing platform chitosan-thionine(chit-thio)/poly(amidoamine) dendrimer-encapsulated AuNPs [PAMAM(Au)] composites were first prepared from chit-thio and PAMAM(Au) using the layer-by-layer method to provide a matrix for high-stability and high-bioactivity bindings of the capture antibody(cAb). Moreover, the {dAb-AuNPs-HRP} nanoprobes were designed to exploit the amplification effect of the carrier AuNPs due to the loading amounts of horseradish peroxidase(HRP)and the detection antibody(dAb). The sandwich-type immunoassay was then successfully used to assay E. coli based on the oxidation of thionine as a result of H2O2-induced enzymatic catalytic reaction by HRP. This study presents a powerful tool in electrochemical immunoassay for E. coli detection with rapid response, high-sensitivity and high-specificity, providing a potential new tool for feasibility assessment of sludge recycle.展开更多
Enzymatic malonylation of natural glycosides provides a promising alternative method for drug-like malonylated glycosides supply.However,the catalytic potential and structural basis of plant malonyltransferase are far...Enzymatic malonylation of natural glycosides provides a promising alternative method for drug-like malonylated glycosides supply.However,the catalytic potential and structural basis of plant malonyltransferase are far from being fully elucidated.This work identified a new malonyltransferase CtMaT1 from Cistanche tubulosa.It displayed unprecedented mono-and/or di-malonylation activity toward diverse glucosides with different aglycons.A“one-pot”system by CtMaT1 and a malonyl-CoA synthetase was established to biosynthesize nine new malonylated glucosides.Structural investigations revealed that CtMaT1 possesses an adequately spacious acyl-acceptor pocket capable of accommodating diverse glucosides.Additionally,it recognizes malonyl-CoA through strong electrotactic and hydrogen interactions.QM/MM calculation revealed the H167-mediated SN2 reaction mechanism of CtMaT1,while dynamic simulations detected the formation of stable hydrogen bonds between the glucose-6-OH group and H167,resulting in its high malonylation regiospecificity.Calculated energy profiles of two isomeric glycosides highlighted lower reaction energy barriers towards glucoside substrates,emphasizing CtMaT1's preference for glucosides.Furthermore,a mutant CtMaT1H36A with notably increased di-malonylation activity was obtained.The underlying molecular mechanism was illuminated through MM/GBSA binding free energy calculation.This study significantly advances the understanding of plant acyltransferases from both functional and protein structural perspectives,while also providing a versatile tool for enzymatic malonylation applications in pharmacology.展开更多
Chiral benzothiazepines constitute the core structures of many foremost pharmaceuticals with diverse biological activities endowed by their unique scaffolds,which poses a great challenge to organic chemists and pharma...Chiral benzothiazepines constitute the core structures of many foremost pharmaceuticals with diverse biological activities endowed by their unique scaffolds,which poses a great challenge to organic chemists and pharmaceutical researchers.This review provides a concise overview for the asymmetric synthesis of chiral benzothiazepine derivatives,focusing on advances in asymmetric catalysis,including metal catalysis,small-molecule organocatalysis and enzymatic catalysis.The catalytic asymmetric reactions,involving asymmetric epoxidation,reduction,dihydroxylation,hydrogenation,aldol reaction and other sulfa-Michael addition,have emerged as powerful strategies for the rapid construction of chiral benzothiazepine through single or multistep reactions.The booming asymmetric synthetic methodology affords us instructive clues for the highly efficient preparation of chiral benzothiazepines,facilitating their large-scale preparation and diversity-oriented synthesis.展开更多
Enzyme-catalysis self-assembled oligopeptide hydrogel holds great interest in drug delivery,which has merits of biocompatibility,biodegradability and mild gelation conditions.However,its application for protein delive...Enzyme-catalysis self-assembled oligopeptide hydrogel holds great interest in drug delivery,which has merits of biocompatibility,biodegradability and mild gelation conditions.However,its application for protein delivery is greatly limited by inevitable degradation of enzyme on the encapsulated proteins leading to loss of protein activity.Moreover,for the intracellularly acted proteins,cell membrane as a primary barrier hinders the transmembrane delivery of proteins.The internalized proteins also suffer from acidic and enzymatic degradation in endosomes and lysosomes.We herein develop a proteasemanipulated hybrid nanogel/nanofiber hydrogel for localized delivery of intracellularly acted proteins.The embedded polymeric nanogels(CytoC/aNGs)preserve activity of cytochrome c(CytoC)that is an intracellular activator for cell apoptosis as a model protein against proteolysis,and do not affect the gelation properties of the protease-catalysis assembled hydrogels.The injectable hydrogel(CytoC/aNGs/Gel)serves as a reservoir to enhance intratumoral retention and realize sustainable release of CytoC/aNGs.The released CytoC/aNGs increase cellular uptake of CytoC and enhance its intracellular delivery to its target site,cytoplasm,resulting in favorable apoptosis-inducing and cytotoxic effects.We show that a single local administration of CytoC/aNGs/Gel efficiently inhibit the tumor growth in the breast tumor mouse model.展开更多
A simple and efficient method using enzyme immobilized microfluidic channel as open tubular microreactor was designed for amperometric detection of glucose. The microreactor was composed of a polydimethylsilicone/ gla...A simple and efficient method using enzyme immobilized microfluidic channel as open tubular microreactor was designed for amperometric detection of glucose. The microreactor was composed of a polydimethylsilicone/ glass hybrid device with three reservoirs, a cooling cave and a 6 cm capillary with a sampling fracture as micro-channel. The microchannel was further modified by thermal polymerization, followed by covalently attaching with glucose oxidase. Through fracture sampling and electrochromatography separation, the production via enzymatic reaction was determinated by Pt electrode at the end of capillary. The linear range for the detection of glucose was 0.05--7.5 mmol·L-1 with detection limit of 23μmol.L-1 The inter-and intra-chip reproducibilities for determination of 2.5 mmol-L-1 glucose were 98.5% (n=5) and 96.0% (n=5), respectively. With the advantage of flexible assembly, rapid efficiency, good stability and low-cost, this microreactor provided a potential platform for estab- lishing a portable enzyme-based chemical detection system in practical application.展开更多
基金Supported by Jiangxi Provincial Engineering & Technology Research Center for Food Additives Bio-ProductionScience & Technology Platform Construction Program of Jiangxi Province (2010DTZ01900)+1 种基金Priority Academic Program Development of Jiangsu Higher Education InstitutionsResearch Foundation for Advanced Talents of Jiangsu University (08JDG029)~~
文摘Non-aqueous phase enzymatic catalysis technology has been widely ap- plied in the area of food additives production. This paper reviewed the types of re- action medium of non-aqueous phase enzymatic catalysis reaction, introduced the application of non-aqueous phase enzymatic catalysis technology in catalysis of L-ascorbic (isoascorbic) acid esters, short-chain acid esters, sugar esters, vitamin A esters, vi- tamin E esters, and other food additives, and finally predicted the prospects of non- aqueous phase enzymatic catalysis technology.
文摘Biodiesel is an excellent option for reducing dependence on fossil fuels with environmental advantages by reducing hazardous emissions. The enzymatic transesterification has attracted the attention of researchers in the last decade and the advantages of enzymatic catalysis show that the production of biodiesel by this route has good potential, mainly because it is friendly environment. For biodiesel, production process by enzyme catalysis is chosen the response surface methodology. It is an experimental strategy to find the best operating conditions oftransesterification reaction to improve the biodiesel quality. The Process has three variables: temperature, molar ratio oil-alcohol and catalyst quantity. The process was monitored by GC-FID (gas chromatography with flame ionization detector). The yield of the transesterification reaction by enzymatic catalysis decreases with increasing temperature, and may be due to inactivation of the enzyme by denaturation at temperatures above 50 ℃. The second-order design used was the "CDC (central design composition)" which produced a maximum yield of 95.5% in the transesterification reaction by enzymatic catalysis obtained at a temperature of 45 ℃, molar ratio methanol:oil of 8:1 and a catalyst loading of 8% wt.
文摘Currently, biodiesel is presented as one of the best alternatives for gradually replacing the use of fossil fuels, but it has some factors that make it economically impractical if it does not have a government support. For this reason, research efforts focused on this area have been responsible for optimizing the process of biodiesel production by different catalytic routes to achieve greater efficiency at a lower cost. In this case, the biggest problem has been the high cost generated by an investigation, which in many occasions is the main factor to decide if an investigation could be carried out. Trying to reduce these costs, in the current study, we are using a technique of glycerol quantification by volumetric methods and comparing obtained results with the chromatographic method, which is conventionally used and comparatively much more expensive. Biodiesel employee was obtained by an enzymatic catalysis process varying one of three process variables:oil:alcohol molar ratio, temperature and proportion of catalyst. The numerical differences obtained between the two quantification methods generated relative errors lower than 10%, resulting in some occasions lower than 1%. By gas chromatography analysis the best yield was obtained at the same conditions of the volumetric method, a temperature of 45 ℃, an oil:alcohol ratio 1:4 and 8 wt.% of catalyst, but a yield of 95.5% and 97.1%, respectively. Due to the high precision of gas chromatography, this method is used to carry out a surface response analysis obtaining as ideal operating conditions a temperature of 43.5 ℃, 8.9 wt.%. of catalyst and an oil:alcohol ratio 1:4.
基金the Natural Science Foundation of Guangdong Province (No. 020839).
文摘Ionic liquids have negligibly low vapor pressure, high stability and polarity. They are regarded as green solvents. Enzymes, especially lipases, as well as whole-cell of microbe, are catalytically active in ionic liquids or aqueous-ionic liquid biphasic systems. Up to date, there have been many reports on enzyme-exhibited features and enzyme-mediated reactions in ionic liquids. In many cases, remarkable results with respect to yield, catalytic activity, stability and (enantio-, regio-) selectivity were obtained in ionic liquids in comparison with those observed in conventional media. Accordingly, ionic liquids provide new possibilities for the application of new type of solvent in biocatalytic reactions.
文摘hoton emission properties of polyphenylphenol (PPP) synthesized in the pres-ence of a newly-found enzymatic catalyst are reported. The photoluminescence peakexcited by the light at 350 nm is at about 370-420 nm. The absorption band edgesand photon emitting peaks of the polymer were found dependent on the conjugatedlengths of the polymer. In the transient luminescence measurement the lifetime ofPL decay was determined to be 2. 0 ns which is supposed as the evidence of polaronexcitation recombination.
基金Supported by the National Natural Science Foundation of China(Nos.21205051, 51608235) and the Key Project of the Ministry of Education of China(No.210078).
文摘An electrochemical immunosensor was developed for sensitive assay ofE. coli in urban sludge, in which electron mediator-mediated enzymatic catalysis and gold nanoparticles(AuNPs) were utilized for signal amplification. The immnuosensing platform chitosan-thionine(chit-thio)/poly(amidoamine) dendrimer-encapsulated AuNPs [PAMAM(Au)] composites were first prepared from chit-thio and PAMAM(Au) using the layer-by-layer method to provide a matrix for high-stability and high-bioactivity bindings of the capture antibody(cAb). Moreover, the {dAb-AuNPs-HRP} nanoprobes were designed to exploit the amplification effect of the carrier AuNPs due to the loading amounts of horseradish peroxidase(HRP)and the detection antibody(dAb). The sandwich-type immunoassay was then successfully used to assay E. coli based on the oxidation of thionine as a result of H2O2-induced enzymatic catalytic reaction by HRP. This study presents a powerful tool in electrochemical immunoassay for E. coli detection with rapid response, high-sensitivity and high-specificity, providing a potential new tool for feasibility assessment of sludge recycle.
基金This work was financially supported by National Key Research and Development Program Special Project of Synthetic Biology(Grant No.2023YFA0914100/2023YFA0914103)National Natural Science Foundation of China(Grant No.82173922,81402809)+3 种基金Beijing Natural Science Foundation(Grant No.7192112)Fundamental Research Funds for the Central Universities(Grant No.2023-JYB-JBQN-054,China)Young Elite Scientists Sponsorship Program by CAST(Grant No.CACM-2018-QNRC1-02,China)State Key Laboratory of Natural and Biomimetic Drugs Foundation(Grant No.K202119,China).
文摘Enzymatic malonylation of natural glycosides provides a promising alternative method for drug-like malonylated glycosides supply.However,the catalytic potential and structural basis of plant malonyltransferase are far from being fully elucidated.This work identified a new malonyltransferase CtMaT1 from Cistanche tubulosa.It displayed unprecedented mono-and/or di-malonylation activity toward diverse glucosides with different aglycons.A“one-pot”system by CtMaT1 and a malonyl-CoA synthetase was established to biosynthesize nine new malonylated glucosides.Structural investigations revealed that CtMaT1 possesses an adequately spacious acyl-acceptor pocket capable of accommodating diverse glucosides.Additionally,it recognizes malonyl-CoA through strong electrotactic and hydrogen interactions.QM/MM calculation revealed the H167-mediated SN2 reaction mechanism of CtMaT1,while dynamic simulations detected the formation of stable hydrogen bonds between the glucose-6-OH group and H167,resulting in its high malonylation regiospecificity.Calculated energy profiles of two isomeric glycosides highlighted lower reaction energy barriers towards glucoside substrates,emphasizing CtMaT1's preference for glucosides.Furthermore,a mutant CtMaT1H36A with notably increased di-malonylation activity was obtained.The underlying molecular mechanism was illuminated through MM/GBSA binding free energy calculation.This study significantly advances the understanding of plant acyltransferases from both functional and protein structural perspectives,while also providing a versatile tool for enzymatic malonylation applications in pharmacology.
基金The support from the National Natural Science Foundation of China(No.21877087)is greatly appreciated.
文摘Chiral benzothiazepines constitute the core structures of many foremost pharmaceuticals with diverse biological activities endowed by their unique scaffolds,which poses a great challenge to organic chemists and pharmaceutical researchers.This review provides a concise overview for the asymmetric synthesis of chiral benzothiazepine derivatives,focusing on advances in asymmetric catalysis,including metal catalysis,small-molecule organocatalysis and enzymatic catalysis.The catalytic asymmetric reactions,involving asymmetric epoxidation,reduction,dihydroxylation,hydrogenation,aldol reaction and other sulfa-Michael addition,have emerged as powerful strategies for the rapid construction of chiral benzothiazepine through single or multistep reactions.The booming asymmetric synthetic methodology affords us instructive clues for the highly efficient preparation of chiral benzothiazepines,facilitating their large-scale preparation and diversity-oriented synthesis.
基金supported by the National Key Research and Development Program of China(No.2019YFA0905200)the National Natural Science Foundation of China(No.81971730,No.81503012)+1 种基金the Natural Science Foundation of Jiangsu Province of China for Excellent Young Scholars(No.BK20190084)the Young Elite Scientists Sponsorship Program by CAST(China)
文摘Enzyme-catalysis self-assembled oligopeptide hydrogel holds great interest in drug delivery,which has merits of biocompatibility,biodegradability and mild gelation conditions.However,its application for protein delivery is greatly limited by inevitable degradation of enzyme on the encapsulated proteins leading to loss of protein activity.Moreover,for the intracellularly acted proteins,cell membrane as a primary barrier hinders the transmembrane delivery of proteins.The internalized proteins also suffer from acidic and enzymatic degradation in endosomes and lysosomes.We herein develop a proteasemanipulated hybrid nanogel/nanofiber hydrogel for localized delivery of intracellularly acted proteins.The embedded polymeric nanogels(CytoC/aNGs)preserve activity of cytochrome c(CytoC)that is an intracellular activator for cell apoptosis as a model protein against proteolysis,and do not affect the gelation properties of the protease-catalysis assembled hydrogels.The injectable hydrogel(CytoC/aNGs/Gel)serves as a reservoir to enhance intratumoral retention and realize sustainable release of CytoC/aNGs.The released CytoC/aNGs increase cellular uptake of CytoC and enhance its intracellular delivery to its target site,cytoplasm,resulting in favorable apoptosis-inducing and cytotoxic effects.We show that a single local administration of CytoC/aNGs/Gel efficiently inhibit the tumor growth in the breast tumor mouse model.
文摘A simple and efficient method using enzyme immobilized microfluidic channel as open tubular microreactor was designed for amperometric detection of glucose. The microreactor was composed of a polydimethylsilicone/ glass hybrid device with three reservoirs, a cooling cave and a 6 cm capillary with a sampling fracture as micro-channel. The microchannel was further modified by thermal polymerization, followed by covalently attaching with glucose oxidase. Through fracture sampling and electrochromatography separation, the production via enzymatic reaction was determinated by Pt electrode at the end of capillary. The linear range for the detection of glucose was 0.05--7.5 mmol·L-1 with detection limit of 23μmol.L-1 The inter-and intra-chip reproducibilities for determination of 2.5 mmol-L-1 glucose were 98.5% (n=5) and 96.0% (n=5), respectively. With the advantage of flexible assembly, rapid efficiency, good stability and low-cost, this microreactor provided a potential platform for estab- lishing a portable enzyme-based chemical detection system in practical application.