Porcine pancreas lipase(PPL) immobilized on narrow distributed micron glass beads was employed successfully for ring-opening polymerization of ε-caprolactone(CL).Different polymerization conditions such as enzyme con...Porcine pancreas lipase(PPL) immobilized on narrow distributed micron glass beads was employed successfully for ring-opening polymerization of ε-caprolactone(CL).Different polymerization conditions such as enzyme concentration,reaction temperature and reaction time were studied.The results showed that M_n of the resulting PCL was significantly increased compared with that catalyzed by PPL.Higher temperature and longer reaction time both contributed to gaining PCL with a higher molecular weight,while the yield had almost no change.In addition,for evaluating the recyclibilty of immobilized PPL on narrow distributed micron glass beads for the ring-opening polymerization of CL,we adopted the most severe reaction conditions(180 ℃,(240 h)) in the recycling experiments.It was found that the recovered immobilized PPL could be used again with a compatible high catalytic activity.The highest M_n of 21 300 of PCL could be obtained at a mass fraction of 5.18% of the reused immobilized PPL at 180 ℃ for 240 h,which is the highest M_n of PCL catalyzed by PPL.The excellent recyclability of immobilized PPL on narrow distributed micron glass beads is very helpful to its further industry applications.展开更多
对12月龄SD大鼠给予L-苹果酸30d后,采用含有SYBR Green I的Real Time RT-PCR法,对肝脏和心脏线粒体苹果酸天冬氨酸穿梭中的两种转运蛋白(天冬氨酸谷氨酸转运蛋白(AGC)与α-酮戊二酸苹果酸转运蛋白(OMC))以及两种抗氧化酶(过氧化氢酶(CAT...对12月龄SD大鼠给予L-苹果酸30d后,采用含有SYBR Green I的Real Time RT-PCR法,对肝脏和心脏线粒体苹果酸天冬氨酸穿梭中的两种转运蛋白(天冬氨酸谷氨酸转运蛋白(AGC)与α-酮戊二酸苹果酸转运蛋白(OMC))以及两种抗氧化酶(过氧化氢酶(CAT)和谷胱甘肽过氧化物酶(GSH-Px))的基因表达进行检测,以研究L-苹果酸增强线粒体抗氧化作用的分子生物学机制。结果表明:苹果酸组中大鼠心肌细胞AGC、OMC、CAT、GSH-Px的mRNA表达量分别是空白对照组的1.25、1.39、1.12、1.01倍。苹果酸组中大鼠肝脏细胞AGC、OMC、CAT、GSH-Px的mRNA表达量分别是空白对照组的1.33、1.02、1.25、0.94倍。由此推测,L-苹果酸可能通过促进苹果酸天冬氨酸穿梭蛋白以及抗氧化酶的基因表达,实现提高线粒体的抗氧化作用。展开更多
文摘Porcine pancreas lipase(PPL) immobilized on narrow distributed micron glass beads was employed successfully for ring-opening polymerization of ε-caprolactone(CL).Different polymerization conditions such as enzyme concentration,reaction temperature and reaction time were studied.The results showed that M_n of the resulting PCL was significantly increased compared with that catalyzed by PPL.Higher temperature and longer reaction time both contributed to gaining PCL with a higher molecular weight,while the yield had almost no change.In addition,for evaluating the recyclibilty of immobilized PPL on narrow distributed micron glass beads for the ring-opening polymerization of CL,we adopted the most severe reaction conditions(180 ℃,(240 h)) in the recycling experiments.It was found that the recovered immobilized PPL could be used again with a compatible high catalytic activity.The highest M_n of 21 300 of PCL could be obtained at a mass fraction of 5.18% of the reused immobilized PPL at 180 ℃ for 240 h,which is the highest M_n of PCL catalyzed by PPL.The excellent recyclability of immobilized PPL on narrow distributed micron glass beads is very helpful to its further industry applications.
文摘对12月龄SD大鼠给予L-苹果酸30d后,采用含有SYBR Green I的Real Time RT-PCR法,对肝脏和心脏线粒体苹果酸天冬氨酸穿梭中的两种转运蛋白(天冬氨酸谷氨酸转运蛋白(AGC)与α-酮戊二酸苹果酸转运蛋白(OMC))以及两种抗氧化酶(过氧化氢酶(CAT)和谷胱甘肽过氧化物酶(GSH-Px))的基因表达进行检测,以研究L-苹果酸增强线粒体抗氧化作用的分子生物学机制。结果表明:苹果酸组中大鼠心肌细胞AGC、OMC、CAT、GSH-Px的mRNA表达量分别是空白对照组的1.25、1.39、1.12、1.01倍。苹果酸组中大鼠肝脏细胞AGC、OMC、CAT、GSH-Px的mRNA表达量分别是空白对照组的1.33、1.02、1.25、0.94倍。由此推测,L-苹果酸可能通过促进苹果酸天冬氨酸穿梭蛋白以及抗氧化酶的基因表达,实现提高线粒体的抗氧化作用。
