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Aliphatic Aldehyde
The Experts below are selected from a list of 135 Experts worldwide ranked by ideXlab platform
Yuqi Feng – 1st expert on this subject based on the ideXlab platform
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determination of low Aliphatic Aldehyde derivatizatives in human saliva using polymer monolith microextraction coupled to high performance liquid chromatography
Analytica Chimica Acta, 2006Co-Authors: Huijuan Zhang, Jingfang Huang, Hong Wang, Yuqi FengAbstract:Abstract In this study, a polymer monolith microextraction (PMME) using a poly (methacrylic acid–ethylene glycol dimethacrylate) (MAA–EGDMA) monolith in conjunction with high-performance liquid chromatography (HPLC) was developed for the determination of 2,4-dinitrophenylhydrazine (DNPH) derivatives of several Aldehydes in human saliva. The conditions for the labeling reactions of Aldehydes with DNPH and followed extraction of the derivatives were optimized. The precision, recovery and detection limits were evaluated with spiked saliva. The limits of detection ranged from 0.43 to 1.40 μg/L. The inter-and intra-day relative standard deviations were less than 10%. The proposed method was successfully applied to the determination of Aldehydes in saliva samples from a non-smoker, a passive smoker and a heavy smoker.
Dong Yi – 2nd expert on this subject based on the ideXlab platform
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second generation engineering of a thermostable transketolase tkgst for Aliphatic Aldehyde acceptors with either improved or reversed stereoselectivity
ChemBioChem, 2017Co-Authors: Chaoqiang Zhou, Wolfdieter Fessner, Thangavelu Saravanan, Franck Charmantray, Laurence Hecquet, Marion Lorilliere, Dong YiAbstract:The transketolase from Geobacillus stearothermophilus (TKGst) is a thermostable enzyme with notable high activity and stability at elevated temperatures, but it accepts non-α-hydroxylated Aldehydes only with low efficiency. Here we report a protein engineering study of TKGst based on double-site saturation mutagenesis either at Leu191 or at Phe435 in combination with Asp470; these are the residues responsible for substrate binding in the active site. Screening of the mutagenesis libraries resulted in several positive variants with activity towards propanal up to 7.4 times higher than that of the wild type. Variants F435L/D470E and L191V/D470I exhibited improved (73 % ee, 3S) and inverted (74 % ee, 3R) stereoselectivity, respectively, for propanal. L191V, L382F/E, F435L, and D470/D470I were concluded to be positive mutations at Leu191, Leu382, Phe435, and Asp470 both for activity and for stereoselectivity improvement. These results should benefit further engineering of TKGst for various applications in asymmetric carboligation.
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a thermostable transketolase evolved for Aliphatic Aldehyde acceptors
Chemical Communications, 2015Co-Authors: Dong Yi, Thangavelu Saravanan, Titu Devamani, Franck Charmantray, Laurence Hecquet, Wolfdieter FessnerAbstract:Directed evolution of the thermostable transketolase from Geobacillus stearothermophilus based on a pH-based colorimetric screening of smart libraries yielded several mutants with up to 16-fold higher activity for Aliphatic Aldehydes and high enantioselectivity (>95% ee) in the asymmetric carboligation step.
Wolfdieter Fessner – 3rd expert on this subject based on the ideXlab platform
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second generation engineering of a thermostable transketolase tkgst for Aliphatic Aldehyde acceptors with either improved or reversed stereoselectivity
ChemBioChem, 2017Co-Authors: Chaoqiang Zhou, Wolfdieter Fessner, Thangavelu Saravanan, Franck Charmantray, Laurence Hecquet, Marion Lorilliere, Dong YiAbstract:The transketolase from Geobacillus stearothermophilus (TKGst) is a thermostable enzyme with notable high activity and stability at elevated temperatures, but it accepts non-α-hydroxylated Aldehydes only with low efficiency. Here we report a protein engineering study of TKGst based on double-site saturation mutagenesis either at Leu191 or at Phe435 in combination with Asp470; these are the residues responsible for substrate binding in the active site. Screening of the mutagenesis libraries resulted in several positive variants with activity towards propanal up to 7.4 times higher than that of the wild type. Variants F435L/D470E and L191V/D470I exhibited improved (73 % ee, 3S) and inverted (74 % ee, 3R) stereoselectivity, respectively, for propanal. L191V, L382F/E, F435L, and D470/D470I were concluded to be positive mutations at Leu191, Leu382, Phe435, and Asp470 both for activity and for stereoselectivity improvement. These results should benefit further engineering of TKGst for various applications in asymmetric carboligation.
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a thermostable transketolase evolved for Aliphatic Aldehyde acceptors
Chemical Communications, 2015Co-Authors: Dong Yi, Thangavelu Saravanan, Titu Devamani, Franck Charmantray, Laurence Hecquet, Wolfdieter FessnerAbstract:Directed evolution of the thermostable transketolase from Geobacillus stearothermophilus based on a pH-based colorimetric screening of smart libraries yielded several mutants with up to 16-fold higher activity for Aliphatic Aldehydes and high enantioselectivity (>95% ee) in the asymmetric carboligation step.