The production of high-purity propylene glycol monomethyl ether acetate(PMA)through the transesterification of propylene glycol monomethyl ether(PM)and methyl acetate(MeOAc)is traditionally catalyzed by sodium methoxi...The production of high-purity propylene glycol monomethyl ether acetate(PMA)through the transesterification of propylene glycol monomethyl ether(PM)and methyl acetate(MeOAc)is traditionally catalyzed by sodium methoxide.However,the practical application of this method is significantly hindered by the inherent limitations of sodium methoxide,such as its high sensitivity to moisture and propensity for solid precipitation,which impede its effective use in continuous processes.This work proposed a continuous catalytic distillation(CD)process utilizing Amberlyst 15 cation exchange resin as the catalyst.A comprehensive series of reaction kinetic and CD experiments were conducted to evaluate the performance of the proposed process.The results demonstrate that under the optimal operating conditions,namely an ester-to-ether molar ratio of 6:1,a refluxratio of 5:1,a total feed rate of 0.92 g‧min^(-1),and an evaporation rate of 266.47 m^(3)‧m^(-2)‧h^(-1),the conversion rate of PM achieves 99.95%,and the PMA yield is 97.31%.Based on these findings,a process flowsheet for a continuous CD process tailored for the production of electronic-grade PMA is presented.This design incorporates light and heavy removal steps to ensure the production of PMA with a purity of 99.99%.Additionally,the process utilizes pressure swing distillation to recover MeOAc,thereby enhancing the overall efficiencyand sustainability of the production process.The proposed continuous CD process offers a highly efficient,cost-effective,and environmentally sustainable solution for the production of electronic-grade PMA.展开更多
A method for simultaneously analyzing altemariol(AOH), altemariol monomethyl ether (AME) and zearalenone(ZEA) by particle beam LC/MS was established, LC separation was accompiished with a solvent system of methanol an...A method for simultaneously analyzing altemariol(AOH), altemariol monomethyl ether (AME) and zearalenone(ZEA) by particle beam LC/MS was established, LC separation was accompiished with a solvent system of methanol and water (80:20 v/v). The followed particle beam LC/MS analysis gave searchable spectra of AOH. AME and ZEA. Application of this technique to analysis of an alternaria culture confirmed the presence of AOH and AME.展开更多
Dimethyl fumarate （DMF） is a new drug used to treat multiple sclerosis （MS） patients. Here, we examined the effects of DMF and the DMF metabolite monomethyl fumarate （MMF） on various activities of natural killer...Dimethyl fumarate （DMF） is a new drug used to treat multiple sclerosis （MS） patients. Here, we examined the effects of DMF and the DMF metabolite monomethyl fumarate （MMF） on various activities of natural killer （NK） cells. We demonstrated that MMF augments the primary CD56^＋, but not CD56^-, NK cell lysis of K562 and RAJI tumor cells. MMF induced NKp46 expression on the surface of CD56^＋, but not CD56^-, NK cells after incubation for 24 h. This effect was closely correlated with the upregulation of CD107a expression on the surface of CD56＋ NK cells and the induction of Granzyme B release from these cells through this metabolite. An anti-NKp46 antibody inhibited the MMF-induced upregulation of CD107a and the lysis of tumor cells through CD56^＋ NK cells. Thus, these results are the first to show that MMF augments CD56^＋ NK cell lysis of tumor target cells, an effect mediated through NKp46. This novel effect suggests the use of MMF for therapeutic and/or preventive protocols in cancer.展开更多
Protein lysine methylation is a prevalent post-translational modification(PTM)and plays critical roles in all domains of life.However,its extent and function in photosynthetic organisms are still largely unknown.Cyano...Protein lysine methylation is a prevalent post-translational modification(PTM)and plays critical roles in all domains of life.However,its extent and function in photosynthetic organisms are still largely unknown.Cyanobacteria are a large group of prokaryotes that carry out oxygenic photosynthesis and are applied extensively in studies of photosynthetic mechanisms and environmental adaptation.Here we integrated propionylation of monomethylated proteins,enrichment of the modified peptides,and mass spectrometry(MS)analysis to identify monomethylated proteins in Synechocystis sp.PCC 6803(Synechocystis).Overall,we identified 376 monomethylation sites in270 proteins,with numerous monomethylated proteins participating in photosynthesis and carbon metabolism.We subsequently demonstrated that Cpc M,a previously identified asparagine methyltransferase in Synechocystis,could catalyze lysine monomethylation of the potential aspartate aminotransferase Sll0480 both in vivo and in vitro and regulate the enzyme activity of Sll0480.The loss of Cpc M led to decreases in the maximum quantum yield in primary photosystemⅡ(PSⅡ)and the efficiency of energy transfer during the photosynthetic reaction in Synechocystis.We report the first lysine monomethylome in a photosynthetic organism and present a critical database for functional analyses of monomethylation in cyanobacteria.The large number of monomethylated proteins and the identification of Cpc M as the lysine methyltransferase in cyanobacteria suggest that reversible methylation may influence the metabolic process and photosynthesis in both cyanobacteria and plants.展开更多
基金supported by the National Natural Science Foundation of China(22378065,22278077 and 22278076)the Key Program of Natural Science Foundation of Fujian Province of China(2022J02019).
文摘The production of high-purity propylene glycol monomethyl ether acetate(PMA)through the transesterification of propylene glycol monomethyl ether(PM)and methyl acetate(MeOAc)is traditionally catalyzed by sodium methoxide.However,the practical application of this method is significantly hindered by the inherent limitations of sodium methoxide,such as its high sensitivity to moisture and propensity for solid precipitation,which impede its effective use in continuous processes.This work proposed a continuous catalytic distillation(CD)process utilizing Amberlyst 15 cation exchange resin as the catalyst.A comprehensive series of reaction kinetic and CD experiments were conducted to evaluate the performance of the proposed process.The results demonstrate that under the optimal operating conditions,namely an ester-to-ether molar ratio of 6:1,a refluxratio of 5:1,a total feed rate of 0.92 g‧min^(-1),and an evaporation rate of 266.47 m^(3)‧m^(-2)‧h^(-1),the conversion rate of PM achieves 99.95%,and the PMA yield is 97.31%.Based on these findings,a process flowsheet for a continuous CD process tailored for the production of electronic-grade PMA is presented.This design incorporates light and heavy removal steps to ensure the production of PMA with a purity of 99.99%.Additionally,the process utilizes pressure swing distillation to recover MeOAc,thereby enhancing the overall efficiencyand sustainability of the production process.The proposed continuous CD process offers a highly efficient,cost-effective,and environmentally sustainable solution for the production of electronic-grade PMA.
文摘A method for simultaneously analyzing altemariol(AOH), altemariol monomethyl ether (AME) and zearalenone(ZEA) by particle beam LC/MS was established, LC separation was accompiished with a solvent system of methanol and water (80:20 v/v). The followed particle beam LC/MS analysis gave searchable spectra of AOH. AME and ZEA. Application of this technique to analysis of an alternaria culture confirmed the presence of AOH and AME.
文摘Dimethyl fumarate （DMF） is a new drug used to treat multiple sclerosis （MS） patients. Here, we examined the effects of DMF and the DMF metabolite monomethyl fumarate （MMF） on various activities of natural killer （NK） cells. We demonstrated that MMF augments the primary CD56^＋, but not CD56^-, NK cell lysis of K562 and RAJI tumor cells. MMF induced NKp46 expression on the surface of CD56^＋, but not CD56^-, NK cells after incubation for 24 h. This effect was closely correlated with the upregulation of CD107a expression on the surface of CD56＋ NK cells and the induction of Granzyme B release from these cells through this metabolite. An anti-NKp46 antibody inhibited the MMF-induced upregulation of CD107a and the lysis of tumor cells through CD56^＋ NK cells. Thus, these results are the first to show that MMF augments CD56^＋ NK cell lysis of tumor target cells, an effect mediated through NKp46. This novel effect suggests the use of MMF for therapeutic and/or preventive protocols in cancer.
基金the National Natural Science Foundation of China(Grant No.31570829)the Chinese Academy of Sciences Grant QYZDY-SSW-SMC004+1 种基金the CAS Key Technology Talent Program(to MKY)the Open Fund of Key Laboratory of Experimental Marine Biology,Chinese Academy of Sciences(Grant No.KF2017NO3)。
文摘Protein lysine methylation is a prevalent post-translational modification(PTM)and plays critical roles in all domains of life.However,its extent and function in photosynthetic organisms are still largely unknown.Cyanobacteria are a large group of prokaryotes that carry out oxygenic photosynthesis and are applied extensively in studies of photosynthetic mechanisms and environmental adaptation.Here we integrated propionylation of monomethylated proteins,enrichment of the modified peptides,and mass spectrometry(MS)analysis to identify monomethylated proteins in Synechocystis sp.PCC 6803(Synechocystis).Overall,we identified 376 monomethylation sites in270 proteins,with numerous monomethylated proteins participating in photosynthesis and carbon metabolism.We subsequently demonstrated that Cpc M,a previously identified asparagine methyltransferase in Synechocystis,could catalyze lysine monomethylation of the potential aspartate aminotransferase Sll0480 both in vivo and in vitro and regulate the enzyme activity of Sll0480.The loss of Cpc M led to decreases in the maximum quantum yield in primary photosystemⅡ(PSⅡ)and the efficiency of energy transfer during the photosynthetic reaction in Synechocystis.We report the first lysine monomethylome in a photosynthetic organism and present a critical database for functional analyses of monomethylation in cyanobacteria.The large number of monomethylated proteins and the identification of Cpc M as the lysine methyltransferase in cyanobacteria suggest that reversible methylation may influence the metabolic process and photosynthesis in both cyanobacteria and plants.
