Iron is an essential but excessively toxic nutrient. Although iron is rich in nature, the acquisition of iron is a challenge to life. Its solubility is very low because it is mostly in the form of oxidation or hydroxi...Iron is an essential but excessively toxic nutrient. Although iron is rich in nature, the acquisition of iron is a challenge to life. Its solubility is very low because it is mostly in the form of oxidation or hydroxide. In order to overcome this, microorganisms have evolved a variety of iron absorption pathways, the most important of which is the siderophore-dependent iron absorption pathway. Both bacteria and fungi require specific siderophore esterases to encourage the release of iron within the cell. A deeper understanding of siderophore esterases is crucial for the development of new antibacterial and antifungal diagnostic and therapeutic approaches. There have been many recent studies on anti-infectives via siderophore antibiotic couplers in which siderophore esterases have also played an important role, and in this review, we provide an overview of several of the more common iron carriers as well as siderophore esterases in terms of structure as well as function.展开更多
Lipolytic enzymes have attracted enormous attentions because of their ability in ester hydrolysis,ester synthesis,transesterification and other biochemical reactions.Bacteria are important sources of lipolytic enzymes...Lipolytic enzymes have attracted enormous attentions because of their ability in ester hydrolysis,ester synthesis,transesterification and other biochemical reactions.Bacteria are important sources of lipolytic enzymes applied in industry.Here,a novel lipolytic enzyme encoded by esterase gene est1347 was identified in Marinobacter flavimaris WLL162,and was purified and characterized.The lipolytic enzyme Est1347 consisted of 312 amino acid residues and a 21-amino-acids N-terminal signal peptide with a predicted molecular weight of 34.2 kDa.It belongs to family V of bacterial lipolytic enzymes based on the amino acid sequence homology analysis.Est1347 is a mesophilic and alkali-resistant enzyme with the highest activity at 45℃and pH 8.5;it is stable at temperatures below 50℃and pH 7.5–11.0.Est1347 showed a preference for middle-length chain substrate p-NPC10 and a wide range of other substrates.The Km,Vmax,Kcat and Kcat/Km values of Est1347 for p-NPC10 in pH 8.5 at 45℃were 0.9411 mmol L^(−1),1285μmol min^(−1)mg^(−1),698.91 s^(−1)and 743.65 s^(−1)(mmol L^(−1))^(−1),respectively.It is also tolerant to the metal ions,organic solvents and detergents.In conclusion,the esterase Est1347 laid a foundation for further study of bacterial lipolytic enzyme family V.展开更多
This study was aimed to analyze the effect of procyanidin B2(PC)and tannin acid(TA)on the activities of cholesterol esterase(CEase)and the inhibitory mechanisms of enzymatic activity.The interaction mechanisms were in...This study was aimed to analyze the effect of procyanidin B2(PC)and tannin acid(TA)on the activities of cholesterol esterase(CEase)and the inhibitory mechanisms of enzymatic activity.The interaction mechanisms were investigated by enzymatic kinetics,multi-spectroscopy methods,thermodynamics analysis,molecular docking,and dynamic simulations.PC and TA could bind with CEase and inhibit the activity of enzyme in a mixed-competitive manner and non-competitive manner,which was verified by molecular docking simulations and dynamics simulations.Also,PC and TA showed the synergistic inhibition with orlistat.Fluorescence,UVvis and the thermodynamic analysis revealed that the complexes were formed from CEase and inhibitors by noncovalent interaction.As revealed by the circular dichroism results,both PC and TA decreased enzymatic activities by altering the conformations of CEase.The inhibition of PC and TA on CEase might be one mechanism for its cholesterol-lowering effect.展开更多
Butyrylcholinesterase(BChE;EC 3.1.1.8),an enzyme structurally related to acetylcholinesterase,is widely distributed in the human body.It plays a role in the detoxification of chemicals such as succinylcholine,a muscle...Butyrylcholinesterase(BChE;EC 3.1.1.8),an enzyme structurally related to acetylcholinesterase,is widely distributed in the human body.It plays a role in the detoxification of chemicals such as succinylcholine,a muscle relaxant used in anesthetic practice.BChE is well-known due to variant forms of the enzyme with little or no hydrolytic activity which exist in some endogamous communities and result in prolonged apnea following the administration of succinylcholine.Its other functions include the ability to hydrolyze acetylcholine,the cholinergic neurotransmitter in the brain,when its primary hydrolytic enzyme,acetylcholinesterase,is absent.To assess its potential roles,BChE was studied in relation to insulin resistance,type 2 diabetes mellitus,cognition,hepatic disorders,cardiovascular and cerebrovascular diseases,and inflammatory conditions.Individuals who lack the enzyme activity of BChE are otherwise healthy,until they are given drugs hydrolyzed by this enzyme.Therefore,BChE is a candidate for the study of loss-of-function mutations in humans.Studying individuals with variant forms of BChE can provide insights into whether they are protected against metabolic diseases.The potential utility of the enzyme as a biomarker for Alzheimer’s disease and the response to its drug treatment can also be assessed.展开更多
文摘Iron is an essential but excessively toxic nutrient. Although iron is rich in nature, the acquisition of iron is a challenge to life. Its solubility is very low because it is mostly in the form of oxidation or hydroxide. In order to overcome this, microorganisms have evolved a variety of iron absorption pathways, the most important of which is the siderophore-dependent iron absorption pathway. Both bacteria and fungi require specific siderophore esterases to encourage the release of iron within the cell. A deeper understanding of siderophore esterases is crucial for the development of new antibacterial and antifungal diagnostic and therapeutic approaches. There have been many recent studies on anti-infectives via siderophore antibiotic couplers in which siderophore esterases have also played an important role, and in this review, we provide an overview of several of the more common iron carriers as well as siderophore esterases in terms of structure as well as function.
基金supported by the projects from the National Natural Science Foundation of China(No.42230411)the China Ocean Mineral Resources R and D Association(COMRA)Special Foundation(No.DY135-B2-10).
文摘Lipolytic enzymes have attracted enormous attentions because of their ability in ester hydrolysis,ester synthesis,transesterification and other biochemical reactions.Bacteria are important sources of lipolytic enzymes applied in industry.Here,a novel lipolytic enzyme encoded by esterase gene est1347 was identified in Marinobacter flavimaris WLL162,and was purified and characterized.The lipolytic enzyme Est1347 consisted of 312 amino acid residues and a 21-amino-acids N-terminal signal peptide with a predicted molecular weight of 34.2 kDa.It belongs to family V of bacterial lipolytic enzymes based on the amino acid sequence homology analysis.Est1347 is a mesophilic and alkali-resistant enzyme with the highest activity at 45℃and pH 8.5;it is stable at temperatures below 50℃and pH 7.5–11.0.Est1347 showed a preference for middle-length chain substrate p-NPC10 and a wide range of other substrates.The Km,Vmax,Kcat and Kcat/Km values of Est1347 for p-NPC10 in pH 8.5 at 45℃were 0.9411 mmol L^(−1),1285μmol min^(−1)mg^(−1),698.91 s^(−1)and 743.65 s^(−1)(mmol L^(−1))^(−1),respectively.It is also tolerant to the metal ions,organic solvents and detergents.In conclusion,the esterase Est1347 laid a foundation for further study of bacterial lipolytic enzyme family V.
基金supported by the National Basic Research Program of China(‘973’program,2013CB127106)。
文摘This study was aimed to analyze the effect of procyanidin B2(PC)and tannin acid(TA)on the activities of cholesterol esterase(CEase)and the inhibitory mechanisms of enzymatic activity.The interaction mechanisms were investigated by enzymatic kinetics,multi-spectroscopy methods,thermodynamics analysis,molecular docking,and dynamic simulations.PC and TA could bind with CEase and inhibit the activity of enzyme in a mixed-competitive manner and non-competitive manner,which was verified by molecular docking simulations and dynamics simulations.Also,PC and TA showed the synergistic inhibition with orlistat.Fluorescence,UVvis and the thermodynamic analysis revealed that the complexes were formed from CEase and inhibitors by noncovalent interaction.As revealed by the circular dichroism results,both PC and TA decreased enzymatic activities by altering the conformations of CEase.The inhibition of PC and TA on CEase might be one mechanism for its cholesterol-lowering effect.
文摘Butyrylcholinesterase(BChE;EC 3.1.1.8),an enzyme structurally related to acetylcholinesterase,is widely distributed in the human body.It plays a role in the detoxification of chemicals such as succinylcholine,a muscle relaxant used in anesthetic practice.BChE is well-known due to variant forms of the enzyme with little or no hydrolytic activity which exist in some endogamous communities and result in prolonged apnea following the administration of succinylcholine.Its other functions include the ability to hydrolyze acetylcholine,the cholinergic neurotransmitter in the brain,when its primary hydrolytic enzyme,acetylcholinesterase,is absent.To assess its potential roles,BChE was studied in relation to insulin resistance,type 2 diabetes mellitus,cognition,hepatic disorders,cardiovascular and cerebrovascular diseases,and inflammatory conditions.Individuals who lack the enzyme activity of BChE are otherwise healthy,until they are given drugs hydrolyzed by this enzyme.Therefore,BChE is a candidate for the study of loss-of-function mutations in humans.Studying individuals with variant forms of BChE can provide insights into whether they are protected against metabolic diseases.The potential utility of the enzyme as a biomarker for Alzheimer’s disease and the response to its drug treatment can also be assessed.
