Esterases are crucial biocatalysts in chiral compound synthesis.Herein,a novel esterase EstSIT01 belonging to family V was identified from Microbacterium chocolatum SIT101 through genome mining and phylogenetic analys...Esterases are crucial biocatalysts in chiral compound synthesis.Herein,a novel esterase EstSIT01 belonging to family V was identified from Microbacterium chocolatum SIT101 through genome mining and phylogenetic analysis.EstSIT01 demonstrated remarkable efficiency in asymmetrically hydrolyzing meso-dimethyl ester[Dimethyl cis-1,3-Dibenzyl-2-imidazolidine-4,5-dicarboxyate],producing over 99%yield and 99%enantiomeric excess(e.e.)for(4S,5R)-monomethyl ester,a crucial chiral intermediate during the synthesis of d-biotin.Notably,the recombinant E.coli expressing EstSIT01 exhibited over 40-fold higher activity than that of the wild strain.EstSIT01 displays a preference for short-chain p-NP esters.The optimal temperature and pH were 45°C and 10.0,with Km and kcat values of 0.147 mmol/L and 5.808 s−1,respectively.Molecular docking and MD simulations suggest that the high stereoselectivity for meso-diester may attribute to the narrow entrance tunnel and unique binding pocket structure.Collectively,EstSIT01 holds great potential for preparing chiral carboxylic acids and esters.展开更多
Two impurities of d-biotin are synthesized:di[3-[(3aS,4S,6aR)-2-oxohexahydrothienoimidazol-4-yl]propyl]acetic acid,4-[(3aS,4S,6aR)-2-oxohexahydrothienoimidazol-4-yl]butane-1,1-dicarboxylic acid.Structure of target com...Two impurities of d-biotin are synthesized:di[3-[(3aS,4S,6aR)-2-oxohexahydrothienoimidazol-4-yl]propyl]acetic acid,4-[(3aS,4S,6aR)-2-oxohexahydrothienoimidazol-4-yl]butane-1,1-dicarboxylic acid.Structure of target compounds are confirmed by 1HNMR.This work further improve the research on the impurities of d-biotin,and can be applied to the quality control and quality assurance of d-biotin.展开更多
目的:研究缺血再灌流时异丙酚对肠上皮细胞凋亡的影响及可能机制.方法:96只成年♂Wistar大鼠,随机分为假手术组、缺血再灌流+生理盐水组(I/R+NS)和I/R+异丙酚组(I/R+Pr).采用夹闭肠系膜上动脉(SMA)的方法制作肠缺血再灌流模型.以上各组...目的:研究缺血再灌流时异丙酚对肠上皮细胞凋亡的影响及可能机制.方法:96只成年♂Wistar大鼠,随机分为假手术组、缺血再灌流+生理盐水组(I/R+NS)和I/R+异丙酚组(I/R+Pr).采用夹闭肠系膜上动脉(SMA)的方法制作肠缺血再灌流模型.以上各组分别在再灌流后0,30,60,120和240 min(每时间点8只)处死动物取肠袋组织.采用病理学方法观察肠上皮细胞损伤指数;原位DNA末端标记法(TUNEL)检测肠上皮细胞凋亡率的变化;免疫组化法检测肠上皮细胞Caspase-3,bcl-2表达的变化.结果:I/R+Pr组与I/R+NS组相比,肠上皮细胞病理变化较轻,肠上皮细胞的凋亡率明显下降(P<0.01),再灌流后0,30,60,120和240 min肠上皮细胞中Caspase-3阳性细胞数明显减少(104.4±5.3 vs 146.4±7.6;97.4±6.2 vs 130.4±7.4;134.4±5.1 vs 170.4±8.1;125.4±6.2 vs 160.4±9.5:101±5.8 vs 120.4±8.2,均P<0.01),而bcl-2阳性细胞数明显增加(13.34±4.12 vs 6.72±2.59;14.96±4.85 vs 8.24±3.13;15.29±5.28 vs 9.63±2.89;10.39±3.61 vs 9.63±2.89;10.39±3.61 vs 5.96±1.93;11.08±4.83 vs 6.87±2.43,均P<0.01).结论:异丙酚能抑制缺血再灌流时肠上皮细胞Caspase-3表达,而增加bcl-2表达,减少肠上皮细胞的凋亡.展开更多
Three new impurities of d-Biotin were synthesized:(2S,3S,4S)-5-(3,4-diamino-tetrahydro-thiophen-2-yl)-pentanoic acid,(3aS,4S,6aR)-hexahydro-1-thia-3,4a-diaza-cyclopenta inden-4-one and(3aS,4S,6aR)-4-(5’-Oxo-hexyl)-te...Three new impurities of d-Biotin were synthesized:(2S,3S,4S)-5-(3,4-diamino-tetrahydro-thiophen-2-yl)-pentanoic acid,(3aS,4S,6aR)-hexahydro-1-thia-3,4a-diaza-cyclopenta inden-4-one and(3aS,4S,6aR)-4-(5’-Oxo-hexyl)-tetrahydro-thieno-imidazol-2-one.Structures of target compounds were confirmed by NMR and so on.Our work further improved the research on the impurities of d-biotin,and can be applied to the quality control and quality assurance of d-biotin.展开更多
基金supported by the Shanghai Committee of Science and Technology(No.13430503400)Project of Leading Talents in Shandong Taishan Industry(Grant No.LJNY202019)+1 种基金the Scientific Research Foundation for the Returned Overseas Chinese Scholars,State Education Ministry(No.ZX2012-05)Innovation Program of Shanghai Municipal Education Commission(No.11YZ227).
文摘Esterases are crucial biocatalysts in chiral compound synthesis.Herein,a novel esterase EstSIT01 belonging to family V was identified from Microbacterium chocolatum SIT101 through genome mining and phylogenetic analysis.EstSIT01 demonstrated remarkable efficiency in asymmetrically hydrolyzing meso-dimethyl ester[Dimethyl cis-1,3-Dibenzyl-2-imidazolidine-4,5-dicarboxyate],producing over 99%yield and 99%enantiomeric excess(e.e.)for(4S,5R)-monomethyl ester,a crucial chiral intermediate during the synthesis of d-biotin.Notably,the recombinant E.coli expressing EstSIT01 exhibited over 40-fold higher activity than that of the wild strain.EstSIT01 displays a preference for short-chain p-NP esters.The optimal temperature and pH were 45°C and 10.0,with Km and kcat values of 0.147 mmol/L and 5.808 s−1,respectively.Molecular docking and MD simulations suggest that the high stereoselectivity for meso-diester may attribute to the narrow entrance tunnel and unique binding pocket structure.Collectively,EstSIT01 holds great potential for preparing chiral carboxylic acids and esters.
文摘Two impurities of d-biotin are synthesized:di[3-[(3aS,4S,6aR)-2-oxohexahydrothienoimidazol-4-yl]propyl]acetic acid,4-[(3aS,4S,6aR)-2-oxohexahydrothienoimidazol-4-yl]butane-1,1-dicarboxylic acid.Structure of target compounds are confirmed by 1HNMR.This work further improve the research on the impurities of d-biotin,and can be applied to the quality control and quality assurance of d-biotin.
文摘目的:研究缺血再灌流时异丙酚对肠上皮细胞凋亡的影响及可能机制.方法:96只成年♂Wistar大鼠,随机分为假手术组、缺血再灌流+生理盐水组(I/R+NS)和I/R+异丙酚组(I/R+Pr).采用夹闭肠系膜上动脉(SMA)的方法制作肠缺血再灌流模型.以上各组分别在再灌流后0,30,60,120和240 min(每时间点8只)处死动物取肠袋组织.采用病理学方法观察肠上皮细胞损伤指数;原位DNA末端标记法(TUNEL)检测肠上皮细胞凋亡率的变化;免疫组化法检测肠上皮细胞Caspase-3,bcl-2表达的变化.结果:I/R+Pr组与I/R+NS组相比,肠上皮细胞病理变化较轻,肠上皮细胞的凋亡率明显下降(P<0.01),再灌流后0,30,60,120和240 min肠上皮细胞中Caspase-3阳性细胞数明显减少(104.4±5.3 vs 146.4±7.6;97.4±6.2 vs 130.4±7.4;134.4±5.1 vs 170.4±8.1;125.4±6.2 vs 160.4±9.5:101±5.8 vs 120.4±8.2,均P<0.01),而bcl-2阳性细胞数明显增加(13.34±4.12 vs 6.72±2.59;14.96±4.85 vs 8.24±3.13;15.29±5.28 vs 9.63±2.89;10.39±3.61 vs 9.63±2.89;10.39±3.61 vs 5.96±1.93;11.08±4.83 vs 6.87±2.43,均P<0.01).结论:异丙酚能抑制缺血再灌流时肠上皮细胞Caspase-3表达,而增加bcl-2表达,减少肠上皮细胞的凋亡.
文摘Three new impurities of d-Biotin were synthesized:(2S,3S,4S)-5-(3,4-diamino-tetrahydro-thiophen-2-yl)-pentanoic acid,(3aS,4S,6aR)-hexahydro-1-thia-3,4a-diaza-cyclopenta inden-4-one and(3aS,4S,6aR)-4-(5’-Oxo-hexyl)-tetrahydro-thieno-imidazol-2-one.Structures of target compounds were confirmed by NMR and so on.Our work further improved the research on the impurities of d-biotin,and can be applied to the quality control and quality assurance of d-biotin.
