Inhibition of the enzyme COMT （catechol-O-methyltransferase） is an important approach in the treatment of Parkinson＇s disease. A series of potent catechols for COMT may give insight to develop new ways of antiparki...Inhibition of the enzyme COMT （catechol-O-methyltransferase） is an important approach in the treatment of Parkinson＇s disease. A series of potent catechols for COMT may give insight to develop new ways of antiparkinson drug. COMT inhibitors represent a new class of antiparkinson drugs, when they are coadministered with levodopa. Our goal of research is to study the inhibition of catechol-O-methyltransferase by molecular modeling methods. Different molecular modeling tools are used to perform this work （molecular mechanics, molecular dynamics and molecular docking （molegro virtnaldocker））. The results obtained from this work, into which the inhibition of catechol-O-methyltransferase by molecular modeling methods was elucidated, allow us to conclude that different catechols presents a more optimised inhibition of catechol-O-methyltransferase. The results suggest reducing the severity of Parkinson＇s disease.展开更多
Objective To investigate the association between catechol O-methyl transferase（COMT）Val108/158Met polymorphism and P50 sensory gating in patients with schizophrenia.Methods In this study,event-related potentials（ER...Objective To investigate the association between catechol O-methyl transferase（COMT）Val108/158Met polymorphism and P50 sensory gating in patients with schizophrenia.Methods In this study,event-related potentials（ERP）was determined in 139 stable patients with schizophrenia and 165 healthy controls.P50展开更多
Polymethoxyflavones(PMFs)are a type of uncommon dietary flavonoids,characterized by more than one methoxy group,which exist in limited plant species,like Citrus species and Kaempferia parviflora.In addition,different ...Polymethoxyflavones(PMFs)are a type of uncommon dietary flavonoids,characterized by more than one methoxy group,which exist in limited plant species,like Citrus species and Kaempferia parviflora.In addition,different PMFs,such as nobiletin,sinensetin,tangeretin,and casticin,have been isolated from these natural sources.PMFs have received increasing attention due to their multiple bioactivities,such as antioxidant,anti-inflammatory,anti-cancer,metabolic regulatory,immunoregulatory,neuroprotective,and skin protective effects.These bioactivities of PMFs should be associated with the regulation of critical molecular targets and the interaction with gut microbiota.In order to provide a comprehensive and updated review of PMFs,their natural sources,refined extraction,biosynthesis,metabolism,and bioactivities are summarised and discussed,with the emphasis on the molecular mechanisms of PMFs on regulating different chronic diseases.Overall,PMFs may be promising flavonoids to the forefront of nutraceuticals for the prevention and/or treatment of certain human chronic diseases.展开更多
Plants produce diverse flavonoids for defense and stress resistance,most of which have health benefits and are widely used as food additives and medicines.Methylation of the free hydroxyl groups of flavonoids,catalyze...Plants produce diverse flavonoids for defense and stress resistance,most of which have health benefits and are widely used as food additives and medicines.Methylation of the free hydroxyl groups of flavonoids,catalyzed by S-adenosyl-l-methionine-dependent O-methyltransferases(OMTs),significantly affects their physicochemical properties and bioactivities.Soybeans(Glycine max)contain a rich pool of O-methylated flavonoids.However,the OMTs responsible for flavonoid methylation in G.max remain largely unknown.We screened the G.max genome and obtained 22 putative OMT-encoding genes that share a broad spectrum of amino acid identities(25–96%);among them,19 OMTs were successfully cloned and heterologously expressed in Escherichia coli.We used the flavonoids containing the free 3,5,7,8,3′,4′hydroxyl group,such as flavones(luteolin and 7,8-dihydroxyflavone),flavonols(kaempferol and quercetin),flavanones(naringenin and eriodictyol),isoflavonoids(daidzein and glycetein),and caffeic acid as substrates,and 15 OMTs were proven to catalyze at least one substrate.The methylation activities of these GmOMTs covered the 3,7,8,3′,4′-hydroxyl of flavonoids and 7,4′-hydroxyl of isoflavonoids.The systematic characterization of G.max flavonoid OMTs provides insights into the biosynthesis of methylated flavonoids in soybeans and OMT bioparts for the production of methylated flavonoids via synthetic biology.展开更多
Carbazomycins(1-8)are a subgroup of carbazole derivatives that contain oxygen at the C3 and C4 positions and an unusual asymmetric substitution pattern.Several of these compounds exhibit antifungal and antioxidant act...Carbazomycins(1-8)are a subgroup of carbazole derivatives that contain oxygen at the C3 and C4 positions and an unusual asymmetric substitution pattern.Several of these compounds exhibit antifungal and antioxidant activities.To date,no systematic biosynthetic studies have been conducted on carbazomycins.In this study,carbazomycins A and B(1 and 2)were isolated from Streptomyces luteosporeus NRRL 2401 using a one-strain-many-compound(OSMAC)-guided natural product mining screen.A biosynthetic gene cluster(BGC)was iden-tified,and possible biosynthetic pathways for 1 and 2 were proposed.The in vivo genetic manipulation of the O-methyltransferase-encoding gene cbzMT proved indispensable for 1 and 2 biosynthesis.Size exclusion chro-matography indicated that CbzMT was active as a dimer.In vitro biochemical assays confirmed that CbzMT could repeatedly act on the hydroxyl groups at C3 and C4,producing monomethylated 2 and dimethylated 1.Monomethylated carbazomycin B(2)is not easily methylated;however,CbzMT seemingly prefers the dimethy-lation of the dihydroxyl substrate(12)to 1,even with a low conversion efficiency.These findings not only improve the understanding of carbazomycin biosynthesis but also expand the inventory of OMT-catalyzing it-erative methylations on different acceptor sites,paving the way for engineering biocatalysts to synthesize new active carbazomycin derivatives.展开更多
The determination method of catechol by fluorescence quenching was developed.The assay was based on the combination of the unique property of gold nanoparticles with tyrosinase enzymatic reaction.In the presence of ty...The determination method of catechol by fluorescence quenching was developed.The assay was based on the combination of the unique property of gold nanoparticles with tyrosinase enzymatic reaction.In the presence of tyrosinase,the fluorescence of gold nanoparticles was quenched by catechol which can be employed to detect catechol.Under the optimal conditions,a linear range 5.0×10^(-7)-1.0×10^(-3) mol L^(-1) and a detection limit 1.0×10^(-7) mol L^(-1) of catechol were obtained.o-Quinone intermediate produced...展开更多
Ti-containing phosphate（ Ti-P-O ） catalysts with different molar ratios of P to Ti （0--2. 0 ） were synthesized and characterized by XRD, N2-adsorption/desorption, IR and temperature-programmed desorption （TPD） m...Ti-containing phosphate（ Ti-P-O ） catalysts with different molar ratios of P to Ti （0--2. 0 ） were synthesized and characterized by XRD, N2-adsorption/desorption, IR and temperature-programmed desorption （TPD） methods. The catalytic properties of Ti-P-O samples in the vapor-phase O-methylation of catechol with methanol were also studied. The catechol conversion increases with the increase of the molar ratio of P to Ti in a range of 0-0. 33, while a further increase in the P content leads to a decrease of the catalytic activity. Meanwhile, the selectivities of the catalysts to the main product（guaiacol） increase gradually with the increase of the molar ratio of P to Ti. The presence of relatively strong Lewis acidic and/or basic sites in the P-free catalyst should be responsible for the formation of C-alkylation products. The weak acid-base characteristics of the catalysts are favourable for the mono-O-methylation of catechol. In comparison with the Lewis acidic sites, the Bronsted acidic sites on the catalysts are more active for the title reaction.展开更多
Three titanium-containing aluminum phosphate catalysts with a general formula Al 0.77 Ti 0.23 PO 4 were prepared by the sol-gel method at room temperature(APTS), and a nonuniform precipitation procedure at ro...Three titanium-containing aluminum phosphate catalysts with a general formula Al 0.77 Ti 0.23 PO 4 were prepared by the sol-gel method at room temperature(APTS), and a nonuniform precipitation procedure at room temperature(APTR) and under reflux(APTF), respectively. The structural features and the surface properties of the three catalysts were determined by means of the physical adsorption of nitrogen at liquid N 2 temperature, XRD, UV-Vis, NH 3-TPD and IR of adsorbed pyridine. The vapor phase O-alkylation of catechol with ethanol over the prepared catalysts was studied. It was found that the activity and the selectivity of these catalysts are greatly dependent on the preparation method, and catalyst APTF shows the highest activity and selectivity. The characterization evidence indicates that the weak Brnsted acid sites were more effective for the reaction.展开更多
In this study, extractive distillation has been applied to separate catechol （CAT） from carbofuran phenol （CFP） with high purity and yield. The relative volatility of CFP to CAT was measured, and the choice of sep...In this study, extractive distillation has been applied to separate catechol （CAT） from carbofuran phenol （CFP） with high purity and yield. The relative volatility of CFP to CAT was measured, and the choice of separating agents was investigated. The experimental results indicated that CFP/CAT is an azeotropic system with an azeotropic point at 93.40℃/0.400 kPa and an azeotropic mixture containing 49.96% of CFP and 50.04% of CAT. Data from the determination of the relative volatility have shown that separating agents such as diglycol and 4-butylcatechol （4-TBC） are able to increase the relative volatility up to 1.90. In one shot process batch extractive distillation of CFP mixture with 3% （by mass） diglycol as separating agent, the purity and yield of the obtained CFP was 99.0% and 95.0%, respectively, while the distillation without separating agent provided a purity and yield of only 98.0% and 90.0%, respectively, There was no residual separating agent found in the product.展开更多
文摘Inhibition of the enzyme COMT （catechol-O-methyltransferase） is an important approach in the treatment of Parkinson＇s disease. A series of potent catechols for COMT may give insight to develop new ways of antiparkinson drug. COMT inhibitors represent a new class of antiparkinson drugs, when they are coadministered with levodopa. Our goal of research is to study the inhibition of catechol-O-methyltransferase by molecular modeling methods. Different molecular modeling tools are used to perform this work （molecular mechanics, molecular dynamics and molecular docking （molegro virtnaldocker））. The results obtained from this work, into which the inhibition of catechol-O-methyltransferase by molecular modeling methods was elucidated, allow us to conclude that different catechols presents a more optimised inhibition of catechol-O-methyltransferase. The results suggest reducing the severity of Parkinson＇s disease.
文摘Objective To investigate the association between catechol O-methyl transferase（COMT）Val108/158Met polymorphism and P50 sensory gating in patients with schizophrenia.Methods In this study,event-related potentials（ERP）was determined in 139 stable patients with schizophrenia and 165 healthy controls.P50
基金supported by the Local Financial Funds of National Agricultural Science and Technology Center,Chengdu,China(NASC2021KR01)the Agricultural Science and Technology Innovation Program(ASTIP-IUA-2022002)。
文摘Polymethoxyflavones(PMFs)are a type of uncommon dietary flavonoids,characterized by more than one methoxy group,which exist in limited plant species,like Citrus species and Kaempferia parviflora.In addition,different PMFs,such as nobiletin,sinensetin,tangeretin,and casticin,have been isolated from these natural sources.PMFs have received increasing attention due to their multiple bioactivities,such as antioxidant,anti-inflammatory,anti-cancer,metabolic regulatory,immunoregulatory,neuroprotective,and skin protective effects.These bioactivities of PMFs should be associated with the regulation of critical molecular targets and the interaction with gut microbiota.In order to provide a comprehensive and updated review of PMFs,their natural sources,refined extraction,biosynthesis,metabolism,and bioactivities are summarised and discussed,with the emphasis on the molecular mechanisms of PMFs on regulating different chronic diseases.Overall,PMFs may be promising flavonoids to the forefront of nutraceuticals for the prevention and/or treatment of certain human chronic diseases.
基金This work was financially supported by the National Key Research and Development Program of China(Grant No.2018YFA0900700)the National Natural Science Foundation of China(Nos.31901021+1 种基金31921006)the Strategic Biological Resources Service Network Plan of the Chinese Academy of Sciences(Grant No.KFJ-BRP-009).
文摘Plants produce diverse flavonoids for defense and stress resistance,most of which have health benefits and are widely used as food additives and medicines.Methylation of the free hydroxyl groups of flavonoids,catalyzed by S-adenosyl-l-methionine-dependent O-methyltransferases(OMTs),significantly affects their physicochemical properties and bioactivities.Soybeans(Glycine max)contain a rich pool of O-methylated flavonoids.However,the OMTs responsible for flavonoid methylation in G.max remain largely unknown.We screened the G.max genome and obtained 22 putative OMT-encoding genes that share a broad spectrum of amino acid identities(25–96%);among them,19 OMTs were successfully cloned and heterologously expressed in Escherichia coli.We used the flavonoids containing the free 3,5,7,8,3′,4′hydroxyl group,such as flavones(luteolin and 7,8-dihydroxyflavone),flavonols(kaempferol and quercetin),flavanones(naringenin and eriodictyol),isoflavonoids(daidzein and glycetein),and caffeic acid as substrates,and 15 OMTs were proven to catalyze at least one substrate.The methylation activities of these GmOMTs covered the 3,7,8,3′,4′-hydroxyl of flavonoids and 7,4′-hydroxyl of isoflavonoids.The systematic characterization of G.max flavonoid OMTs provides insights into the biosynthesis of methylated flavonoids in soybeans and OMT bioparts for the production of methylated flavonoids via synthetic biology.
基金supported by a grant from the National Key research and development Program of China (2021YFA0909500,2021YFC2100100)National Natural Science Foundation of China (32170077,32170075).
文摘Carbazomycins(1-8)are a subgroup of carbazole derivatives that contain oxygen at the C3 and C4 positions and an unusual asymmetric substitution pattern.Several of these compounds exhibit antifungal and antioxidant activities.To date,no systematic biosynthetic studies have been conducted on carbazomycins.In this study,carbazomycins A and B(1 and 2)were isolated from Streptomyces luteosporeus NRRL 2401 using a one-strain-many-compound(OSMAC)-guided natural product mining screen.A biosynthetic gene cluster(BGC)was iden-tified,and possible biosynthetic pathways for 1 and 2 were proposed.The in vivo genetic manipulation of the O-methyltransferase-encoding gene cbzMT proved indispensable for 1 and 2 biosynthesis.Size exclusion chro-matography indicated that CbzMT was active as a dimer.In vitro biochemical assays confirmed that CbzMT could repeatedly act on the hydroxyl groups at C3 and C4,producing monomethylated 2 and dimethylated 1.Monomethylated carbazomycin B(2)is not easily methylated;however,CbzMT seemingly prefers the dimethy-lation of the dihydroxyl substrate(12)to 1,even with a low conversion efficiency.These findings not only improve the understanding of carbazomycin biosynthesis but also expand the inventory of OMT-catalyzing it-erative methylations on different acceptor sites,paving the way for engineering biocatalysts to synthesize new active carbazomycin derivatives.
基金supported by the National Natural Science Foundation of China(No.20875059)
文摘The determination method of catechol by fluorescence quenching was developed.The assay was based on the combination of the unique property of gold nanoparticles with tyrosinase enzymatic reaction.In the presence of tyrosinase,the fluorescence of gold nanoparticles was quenched by catechol which can be employed to detect catechol.Under the optimal conditions,a linear range 5.0×10^(-7)-1.0×10^(-3) mol L^(-1) and a detection limit 1.0×10^(-7) mol L^(-1) of catechol were obtained.o-Quinone intermediate produced...
基金Supported by the Development Project of Science and Technology of Jilin Province(Nos. 20050309-1 and 20040563), the Spe-cialized Research Fund for the Doctoral Program of Higher Education(No.20040183003), CNPC(No.JTGS 20040010), and the Na-tional Natural Science Foundation of China(No.20403006)
文摘Ti-containing phosphate（ Ti-P-O ） catalysts with different molar ratios of P to Ti （0--2. 0 ） were synthesized and characterized by XRD, N2-adsorption/desorption, IR and temperature-programmed desorption （TPD） methods. The catalytic properties of Ti-P-O samples in the vapor-phase O-methylation of catechol with methanol were also studied. The catechol conversion increases with the increase of the molar ratio of P to Ti in a range of 0-0. 33, while a further increase in the P content leads to a decrease of the catalytic activity. Meanwhile, the selectivities of the catalysts to the main product（guaiacol） increase gradually with the increase of the molar ratio of P to Ti. The presence of relatively strong Lewis acidic and/or basic sites in the P-free catalyst should be responsible for the formation of C-alkylation products. The weak acid-base characteristics of the catalysts are favourable for the mono-O-methylation of catechol. In comparison with the Lewis acidic sites, the Bronsted acidic sites on the catalysts are more active for the title reaction.
基金Supported by the Foundation of Science of Jilin Province Science and Technique Com mittee( No.990 5 4 6 )
文摘Three titanium-containing aluminum phosphate catalysts with a general formula Al 0.77 Ti 0.23 PO 4 were prepared by the sol-gel method at room temperature(APTS), and a nonuniform precipitation procedure at room temperature(APTR) and under reflux(APTF), respectively. The structural features and the surface properties of the three catalysts were determined by means of the physical adsorption of nitrogen at liquid N 2 temperature, XRD, UV-Vis, NH 3-TPD and IR of adsorbed pyridine. The vapor phase O-alkylation of catechol with ethanol over the prepared catalysts was studied. It was found that the activity and the selectivity of these catalysts are greatly dependent on the preparation method, and catalyst APTF shows the highest activity and selectivity. The characterization evidence indicates that the weak Brnsted acid sites were more effective for the reaction.
基金Supported by the National High Technology Research and Development Program of China(2006AA03Z460)
文摘In this study, extractive distillation has been applied to separate catechol （CAT） from carbofuran phenol （CFP） with high purity and yield. The relative volatility of CFP to CAT was measured, and the choice of separating agents was investigated. The experimental results indicated that CFP/CAT is an azeotropic system with an azeotropic point at 93.40℃/0.400 kPa and an azeotropic mixture containing 49.96% of CFP and 50.04% of CAT. Data from the determination of the relative volatility have shown that separating agents such as diglycol and 4-butylcatechol （4-TBC） are able to increase the relative volatility up to 1.90. In one shot process batch extractive distillation of CFP mixture with 3% （by mass） diglycol as separating agent, the purity and yield of the obtained CFP was 99.0% and 95.0%, respectively, while the distillation without separating agent provided a purity and yield of only 98.0% and 90.0%, respectively, There was no residual separating agent found in the product.
