We previously functionally characterized a novel marine microbial GDSL lipase MT6 and identified that the stereo-selectivity of MT6 was opposite to that of other common lipases in trans-esterification reactions.Herein...We previously functionally characterized a novel marine microbial GDSL lipase MT6 and identified that the stereo-selectivity of MT6 was opposite to that of other common lipases in trans-esterification reactions.Herein,we have investigated the use of MT6 in stereo-selective biocatalysis through direct hydrolysis reactions.Notably,the stereo-selectivity of MT6 was also demonstrated to be opposite to that of other common lipases in hydrolysis reactions.Parameters,including temperature,organic co-solvents,pH,ionic strength,catalyst loading,substrate concentration,and reaction time,affecting the enzymatic resolution of racemic 1-phenylethyl acetate were further investigated,with the e.e.of the final（S）-l-Phenylethanol product and the conversion being 97%and 28.5%,respectively,after process optimization.The lengths of side chains of 1-phenylethyl esters greatly affected the stereo-selectivity and conversion during kinetic resolutions.MT6 is a novel marine microbial GDSL lipase exhibiting opposite stereo-selectivities than other common lipases in both trans-esterification reactions and hydrolysis reactions.展开更多
In this contribution, we reported a very simple and small molecule material, 2,5-dimethoxyterephthalaldehyde(DMA). It exhibited a relatively weak fluorescence in solution, while showed a steadily increased green fluor...In this contribution, we reported a very simple and small molecule material, 2,5-dimethoxyterephthalaldehyde(DMA). It exhibited a relatively weak fluorescence in solution, while showed a steadily increased green fluorescence with typical aggregation-induced enhanced emission(AIE) effect for forming a cubic-like microcrystal structure in THF-H2 O mixed solvent.The microcrystals presented significantly higher fluorescence than that of amorphous aggregates. The DMA microcrystals suspension showed a good response to 2,4,6-trinitrophenol(TNP) with a LOD of 1.2×10^(-7) M, which is the best result of TNP detection in aqueous solution. Quantum chemical calculation revealed that DMA is a donor(D)-receptor(A) type molecule with methoxy unit as donor and carbonyl moiety as receptor. Its emission arises from an intramolecular charge transfer(ICT) from methoxy units to carbonyl units. NMR indicated that there is a strong hydrogen bond interaction between DMA and TNP.Hydrogen bond interaction can effectively decrease the intermolecular distance of DMA and TNP, which will increase the efficiency of photoinduced electron transfer(PET) and fluorescence resonance energy transfer(FRET), and hence will be advantageous for its selectivity. The microcrystal induced enhanced emission could be generally used for kinds of target molecules analysis.展开更多
基金supported by the Strategic Priority Research Program of Chinese Academy of Sciences(XDA11030404),the Key Project from Chinese Academy of Sciences(KGZD-EW-606)the National Natural Science Foundation of China(21302199)Guangzhou Science and Technology Plan Projects(201510010012)
文摘We previously functionally characterized a novel marine microbial GDSL lipase MT6 and identified that the stereo-selectivity of MT6 was opposite to that of other common lipases in trans-esterification reactions.Herein,we have investigated the use of MT6 in stereo-selective biocatalysis through direct hydrolysis reactions.Notably,the stereo-selectivity of MT6 was also demonstrated to be opposite to that of other common lipases in hydrolysis reactions.Parameters,including temperature,organic co-solvents,pH,ionic strength,catalyst loading,substrate concentration,and reaction time,affecting the enzymatic resolution of racemic 1-phenylethyl acetate were further investigated,with the e.e.of the final（S）-l-Phenylethanol product and the conversion being 97%and 28.5%,respectively,after process optimization.The lengths of side chains of 1-phenylethyl esters greatly affected the stereo-selectivity and conversion during kinetic resolutions.MT6 is a novel marine microbial GDSL lipase exhibiting opposite stereo-selectivities than other common lipases in both trans-esterification reactions and hydrolysis reactions.
基金supported by the Ministry of Science and Technology (2016YFA0200800)the National Natural Science Foundation of China (51473182, 61731016, 61771460)the Youth Innovation Promotion Association of Chinese Academy of Sciences (2015190)
文摘In this contribution, we reported a very simple and small molecule material, 2,5-dimethoxyterephthalaldehyde(DMA). It exhibited a relatively weak fluorescence in solution, while showed a steadily increased green fluorescence with typical aggregation-induced enhanced emission(AIE) effect for forming a cubic-like microcrystal structure in THF-H2 O mixed solvent.The microcrystals presented significantly higher fluorescence than that of amorphous aggregates. The DMA microcrystals suspension showed a good response to 2,4,6-trinitrophenol(TNP) with a LOD of 1.2×10^(-7) M, which is the best result of TNP detection in aqueous solution. Quantum chemical calculation revealed that DMA is a donor(D)-receptor(A) type molecule with methoxy unit as donor and carbonyl moiety as receptor. Its emission arises from an intramolecular charge transfer(ICT) from methoxy units to carbonyl units. NMR indicated that there is a strong hydrogen bond interaction between DMA and TNP.Hydrogen bond interaction can effectively decrease the intermolecular distance of DMA and TNP, which will increase the efficiency of photoinduced electron transfer(PET) and fluorescence resonance energy transfer(FRET), and hence will be advantageous for its selectivity. The microcrystal induced enhanced emission could be generally used for kinds of target molecules analysis.
