Bismaleimides bearing electron\|donating chromophore moieties, i.e.N,N \|bis(4\|maleimidophenyl)\|methylamine (BMIPMA),and its saturated model compound N,N\| bis(4\|succinimidophenyl)\|methylamine(BSIPMA) were synthes...Bismaleimides bearing electron\|donating chromophore moieties, i.e.N,N \|bis(4\|maleimidophenyl)\|methylamine (BMIPMA),and its saturated model compound N,N\| bis(4\|succinimidophenyl)\|methylamine(BSIPMA) were synthesized and their absorption and fluorescence behaviors were investigated. It was found that BMIPMA possess a strong fluorescence structural self\|quenching effect (SSQE).There is almost no fluorescence emission observed for BMIPMA,whereas its saturated model compound BSIPMA displays a strong fluorescence emission at the same chromophore concentration.On the basis of the SSQE,a new fluorescence approach was developed to monitor the process of the copolymerization of bismaleimides with diamines,which can directly reflect the consumption of the CC bond of maleimide unit.The results agreed well with that obtained by 1H\|NMR measurement pused.展开更多
A support made of mussel-inspired polydopamine-coated magnetic iron oxide nanoparticles （PD-MNPs） was prepared and characterized. The widely used Aspetyillus niger lipase （ANL） was immobilized on the PD-MNPs （ANL...A support made of mussel-inspired polydopamine-coated magnetic iron oxide nanoparticles （PD-MNPs） was prepared and characterized. The widely used Aspetyillus niger lipase （ANL） was immobilized on the PD-MNPs （ANL@PD-MNPs） with a protein loading of 138 mg/g and an activity recovery of 83.6% under optimized conditions. For the immobilization, the pH and immobilization time were investigated. The pH and thermal and storage stability of the ANL@PD-MNPs significant- ly surpassed those of free ANL. The ANL@PD-MNPs had better solvent tolerance than free ANL. The secondary structure of free ANL and ANL@PD-MNPs was analyzed by infrared spectroscopy, A kinetic study demonstrated that the ANL@PD-MNPs had enhanced enzyme-substrate affinity and high catalytic efficiency. The ANL@PD-MNPs was applied as a biocatalyst for the regioselective acylation of dihydromyricetin （DMY） in DMSO and gave a conversion of 79.3%, which was higher than that of previous reports. The ANL@PD-MNPs retained over 55% of its initial activity after 10 cycles of reuse. The ANL@PD-MNPs were readily separated from the reaction system by a magnet. The PD-MNPs is an excellent support for ANL and the resulting ANL@PD-MNPs displayed good potential for the efficient synthesis of dihydromyricetin-3-acetate by enzymatic regioselective acylation.展开更多
文摘Bismaleimides bearing electron\|donating chromophore moieties, i.e.N,N \|bis(4\|maleimidophenyl)\|methylamine (BMIPMA),and its saturated model compound N,N\| bis(4\|succinimidophenyl)\|methylamine(BSIPMA) were synthesized and their absorption and fluorescence behaviors were investigated. It was found that BMIPMA possess a strong fluorescence structural self\|quenching effect (SSQE).There is almost no fluorescence emission observed for BMIPMA,whereas its saturated model compound BSIPMA displays a strong fluorescence emission at the same chromophore concentration.On the basis of the SSQE,a new fluorescence approach was developed to monitor the process of the copolymerization of bismaleimides with diamines,which can directly reflect the consumption of the CC bond of maleimide unit.The results agreed well with that obtained by 1H\|NMR measurement pused.
基金supported by the National Natural Science Foundation of China(21336002,21222606,21376096)the Key Program of Guangdong Natural Science Foundation(S2013020013049)+1 种基金the Fundamental Research Funds for the Chinese Universities(2015PT002,2015ZP009)the Program of State Key Laboratory of Pulp and Paper Engineering(2015C04)~~
文摘A support made of mussel-inspired polydopamine-coated magnetic iron oxide nanoparticles （PD-MNPs） was prepared and characterized. The widely used Aspetyillus niger lipase （ANL） was immobilized on the PD-MNPs （ANL@PD-MNPs） with a protein loading of 138 mg/g and an activity recovery of 83.6% under optimized conditions. For the immobilization, the pH and immobilization time were investigated. The pH and thermal and storage stability of the ANL@PD-MNPs significant- ly surpassed those of free ANL. The ANL@PD-MNPs had better solvent tolerance than free ANL. The secondary structure of free ANL and ANL@PD-MNPs was analyzed by infrared spectroscopy, A kinetic study demonstrated that the ANL@PD-MNPs had enhanced enzyme-substrate affinity and high catalytic efficiency. The ANL@PD-MNPs was applied as a biocatalyst for the regioselective acylation of dihydromyricetin （DMY） in DMSO and gave a conversion of 79.3%, which was higher than that of previous reports. The ANL@PD-MNPs retained over 55% of its initial activity after 10 cycles of reuse. The ANL@PD-MNPs were readily separated from the reaction system by a magnet. The PD-MNPs is an excellent support for ANL and the resulting ANL@PD-MNPs displayed good potential for the efficient synthesis of dihydromyricetin-3-acetate by enzymatic regioselective acylation.
