JOURNAL OF SEPARATION SCIENCE
·
2019
·Vol. 42
·期 23
·3544-3552
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IF 2.516
Xudong Xiao,Zhenqun Li,Ya Liu,Li Jia
An S-mandelic acid imprinted chitosan resin was synthesized by cross-linking chitosan with glutaraldehyde in 2% acetic acid solution. S-Mandelic acid imprinted chitosan resin was used to enantioselectively separate racemic mandelic acid in aqueous medium. When keeping the pH of sample solution (100 mM Tris-H 3 PO 4 ) at 3.5 and adsorption time at 40 min, the enantiomer excess of mandelic acid in supernatant was 78.8%. The adsorption capacities of S-mandelic acid imprinted chitosan resin for S- and R-mandelic acid were determined to be 29.5 and 2.03 mg/g, respectively. While the adsorption capacities of non-imprinted cross-linked chitosan for S- and R-mandelic acid were 2.10 and 2.08 mg/g, respectively. The result suggests that the imprinted caves in S-mandelic acid imprinted chitosan resin are highly matched with S-mandelic acid molecule in space structure and spatial arrangement of action sites. Interestingly, the enantiomer excess value of mandelic acid in supernatant after adsorption of racemic mandelic acid by R-mandelic acid imprinted cross-linked chitosan was 25.4%. The higher enantiomer excess value by S-mandelic acid imprinted chitosan resin suggests that the chiral carbons in chitosan and the imprinted caves in S-mandelic acid imprinted chitosan resin combine to play roles for the enantioselectivity of S-mandelic acid imprinted chitosan resin toward S-mandelic acid. Furthermore, the excellent enantioselectivity of S-mandelic acid imprinted chitosan resin toward S-mandelic acid demonstrates that using chiral chitosan as functional monomer to prepare molecularly imprinted polymers has great potential in enantioseparation of chiral pharmaceuticals.
研究领域:
分析化学
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生物材料学
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产品关联
DOI
PubMed
高影响因子
BIOCHEMICAL ENGINEERING JOURNAL
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2020
·
IF 3.475
Hong-Yan Wang,Yu-Li Xie,Xin Shi,Hong-Ling Shi,Jian-He Xu,Cun-Duo Tang,Lun-Guang Yao,Yun-Chao Kan
Halogenated mandelate and its derivatives are important scaffolds in chemical industry. However, the natural D -mandelate dehydrogenase (DMDH) showed relatively low catalytic activity toward D -o-chloromandelic acid, which largely limits the efficiency of dehydrogenation processes. To improve catalytic activity of Lactobacillus brevis D -mandelate dehydrogenase ( Lb DMDH) toward halogenated substrate, a D -mandelate dehydrogenase mutant Lb DMDH N253S with higher catalytic activity toward D -o-chloromandelic acid was successfully obtained by directed evolution, which was about 29 times of Lb DMDH. In addition, the temperature optimum of Lb DMDH N253S is 50 °C, and closer to the optimal growth temperature for Escherichia coli , indicating that it may be more advantageous in whole cell catalysis using living cells as catalysts. Meanwhile, the K cat value toward D -o-chloromandelic acid of Lb DMDH N253S is 2.08 s −1 , which is significantly higher than the one (0.09 s −1 ) of Lb DMDH, indicating that Lb DMDH N253S displayed higher catalytic efficiency toward D -o-chloromandelic acid. Then, we preliminarily explained the molecular basis for its catalytic performance by in silico design methods. All of these results established a solid foundation for molecular modification of DMDHs and the other industrial enzymes.
研究领域:
生物化学
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酶工程
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分子生物学
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DOI
高影响因子
JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
·
2018
·
IF 3.412
Cun-Duo Tang,Hong-Ling Shi,Jian-He Xu,Zhu-Jin Jiao,Fei Liu,Peng-Ju Ding,Hong-Fei Shi,Lun-Guang Yao,Yun-Chao Kan
d-Mandelate dehydrogenase (DMDH) has the potential to convert d-mandelic acid to phenylglyoxylic acid (PGA), which is a key building block in the field of chemical synthesis and is widely used to synthesize pharmaceutical intermediates or food additives. A novel NAD+-dependent d-mandelate dehydrogenase was cloned from Lactobacillus harbinensi (LhDMDH) by genome mining and expressed in Escherichia coli BL21. After being purified to homogeneity, the oxidation activity of LhDMDH toward d-mandelic acid was approximately 1200 U·mg–1, which was close to four times the activity of the probe. Meanwhile, the kcat/Km value of LhDMDH was 28.80 S–1·mM–1, which was distinctly higher than the probe. By coculturing two E. coli strains expressing LhDMDH and LcLDH, we developed a system for the efficient synthesis of PGA, achieving a 60% theoretical yield and 99% purity without adding coenzyme or cosubstrate. Our data supports the implementation of a promising strategy for the chiral resolution of racemic mandelic acid and the biosynthesis of PGA.
研究领域:
生物化学
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生物技术
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酶学
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微生物学
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产品关联
DOI
PubMed
高影响因子
SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
·
2023
·
IF 4.4
Zhiqiang Wang,Siqi Duan,Ruiting Zhang,Lin Ma,Ke Lin
Chiral molecules play a very important role in biological systems, and more and more chiral drugs are used in the treatment of diseases. Mandelic acid (MA) is an important chiral starting substance or the key intermediate of some chiral drugs, and the rapid detection of its chiral purity is very important in the synthesis, separation and detection of drugs. In this study, we developed a method for rapid determination of chiral purity of MA by Raman spectroscopy, and measured a series of Raman spectra of different chiral MA. Through the analysis, it is found that the OH stretching vibration peak can be used to identify the components of chiral molecules, and the enantiomeric excess ( ee value) obtained is in good agreement with the real value, and the error is about 5%. The experimental detection speed is fast and the efficiency is high. Our work firstly provides a new idea for the purity detection of chiral molecules by the original Raman spectrum.
研究领域:
药物化学
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分析化学
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生物化学
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产品关联
DOI
PubMed
高影响因子
BIOCATALYSIS AND BIOTRANSFORMATION
·
2018
·
IF 1.06
Ou Zhimin,Lan Ma,Yangpin Niu,Jian Cui
(R)-(-)-mandelic acid was synthesized by two-step biotransformation. (R)-(-)-mandelic acid ethyl ester was obtained via asymmetric reduction of ethyl benzoylformate by Saccharomyces cerevisiae CGMCC No. 3361 at the first step. The conversion and enantiomeric excess of R-(-)-mandelic acid ethyl ester reached 99.8% and 100%, respectively. (R)-(-)-mandelic acid was obtained via hydrolysis of (R)-(-)-mandelic acid ethyl ester by Bacillus cereus CGMCC No. 12336 at the second step. The conversion and enantiomeric excess of R-(-)-mandelic acid reached 97.2% and 100%, respectively. Kinetic models were developed for asymmetric reduction of ethyl benzoylformate and hydrolysis of (R)-(-)-mandelic acid ethyl ester. The kinetic models are in good agreement with the experimental data.
研究领域:
生物化学
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微生物学
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有机合成
✓ 已验证
产品关联
DOI
高影响因子
ANALYST
·
2025
·
IF 3.3
Lu Li,Xiaodi Liu,Shijie Xu,Shiming Zhang,Zhuangzhuang Yang,Debao Xiao
Vanillylmandelic acid (VMA) and homovanillic acid (HVA) are biomarkers for the diagnosis and course-of-disease monitoring of malignant tumor neuroblastomas, which endanger infants and children. Herein, we demonstrated a proof-of-concept visual detection of VMA and HVA on an electrochromic basis, in which the viologen 1,1′-dibenzyl-4,4′-bipyridinium dichloride was used as a coloration chromophore. It was found that VMA and HVA can be used as effective electron mediators to improve the electrochromic performance of devices. It is interesting to note that VMA and HVA reduce the driving voltage of electrochromic devices (ECDs) down to −1.0 V, which is lower than that (−2.1 V) achieved without these additives, and the coloration of ECDs is undoubtedly dependent on the concentration of VMA and HVA from 0.8 to 10−6 mol L−1. Thus, this study presents an ECD platform as a breakthrough strategy for the facile, routine and portable visual detection of the neuroblastoma biomarkers VMA and HVA with obvious advantages over other detection techniques such as HPLC/MS used in clinical diagnosis.
研究领域:
医学诊断
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生物化学
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肿瘤学
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DOI
PubMed
高影响因子
APPLIED CATALYSIS A-GENERAL
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2019
·
IF 4.63
Xin Yuan,Panliang Zhang,Weifeng Xu,Kewen Tang
This paper reports the kinetics resolution of ( R , S )-4-methoxymandelic acid (4-MMA) by lipase AK-catalyzed transesterification reaction, using vinyl acetate (VA) as acyl donor in methyl tert-butyl ether (MTBE). Considering the Ping-Pong bi-bi mechanism with 4-methoxymandelic acid inhibition, the kinetic model was established. Kinetic parameters were obtained by fitting time-concentration curves for different initial 4-methoxymandelic acid concentrations. The average relative error below 3.0% indicated that the model predictions were in good agreement with the experimental data. Furthermore, the kinetic model was employed to predict the effects of enzyme loading, initial vinyl acetate concentration and reaction time on enantiomeric excess (ee s ) and conversion of substrate (c), and to optimize the conditions. The excellent results with high conversion of 4-MMA (50.2%) and large enantiomeric excess of substrate (98.6%) were achieved under the optimal conditions.
研究领域:
生物化学
·
有机化学
✓ 已验证
DOI
高影响因子
CHINESE JOURNAL OF OCEANOLOGY AND LIMNOLOGY
·
2016
·Vol. 34
·期 6
·1269-1277
·
IF 0.547
Liang Jiayuan,Sun Aijun,Zhang Yun,Deng Dun,Wang Yongfei,Ma Sanmei,Hu Yunfeng
Genomic mining has identified a novel microbial alkaline esterase from the Indian Ocean. This esterase was overexpressed in E. coli BL21 (DE3) and further functionally characterized. Under optimal conditions (10 mmol/L substrate, pH 6.0, 2 h at 40 °C), this esterase can hydrolyze racemic methyl mandelate to ( R )-methyl mandelate with very high optical purity ( e.e. >99%) and yield (nearly 90%). Interestingly, the stereoselectivity of this esterase is opposite to that of two previously reported lipases that can generate ( S )-methyl mandelate through the hydrolysis of racemic methyl mandelate. No organic solvents or other additives were required to optimize the optical purity and production of the final chiral product ( R )-methyl mandelate, which can potentially simplify the production procedure of ( R )-methyl mandelate catalyzed by esterase.
研究领域:
生物化学
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海洋微生物学
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酶工程
✓ 已验证
DOI
高影响因子
JOURNAL OF CHEMICAL THERMODYNAMICS
·
2022
·
IF 3.269
Yamin Lv,Zhenning Yan,Liyun Liu
Interactions of two active pharmaceutical ingredient ionic liquids (API-ILs) tetradecylpyridinium dl -mandelic acid ([TetPy][MAN]) and cetylpyridinium dl -mandelic acid ([CetPy][MAN]) with some small biomolecules have been studied by using conductometric, density and UV–vis spectroscopic techniques. The chosen small biomolecules are glycine, l -alanine, l -valine, l -leucine and glycylglycine (AAGG). The critical micelle concentration ( cmc ) of [TetPy][MAN] and [CetPy][MAN] in aqueous AAGG solution is calculated from the measured conductance values, thus yielding some thermodynamic parameters of the micellization, such as the standard Gibbs energy change ( Δ G m 0 ) , the standard enthalpy change ( Δ H m 0 ) and the standard entropy change ( Δ S m 0 ) . On the basis of the experimental densities of ternary solutions of (AAGG + API-ILs + water), apparent molar volume at infinite dilution ( V 2 , φ 0 ), apparent molar expansibility at infinite dilution ( E φ 0 ) , transfer partial molar volume ( Δ t V 0 ) and hydration number ( n H ) of AAGG in aqueous API-ILs solution were calculated. The dominant hydrophobic-hydrophilic and hydrophobic-hydrophobic interactions were involved in the investigated systems. The binding constant ( K b ) between AAGG and API-ILs has been calculated from UV–vis spectroscopic data. Effect of some factors including concentration, temperature, molecular structure, etc. on the aforementioned parameters and the existing solvent–solute interaction has been discussed.
研究领域:
生物化学
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药理学
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产品关联
DOI
高影响因子
JOURNAL OF CHEMICAL AND ENGINEERING DATA
·
2016
·
IF 1.835
Kewen Tang,Xiaofeng Feng,Panliang Zhang,Weifeng Xu
Liquid–liquid extraction (LLE) was used for the resolution of α-cyclopentylmandelic acid (α-CPMA) enantiomers, in which environmentally friendly and economical hydroxyethyl-β-cyclodextrin (HE-β-CD) was screened as the optimal selector. The mechanism on equilibrium of the separation system was proposed. Influence of important parameters on the separation performance of α-CPMA enantiomers were investigated (e.g., kinds of solvents for the organic phase, types and concentration of selector, pH of extraction phase, temperature). On the basis of the mechanism proposed, a quantitative model was also built to simulate the separation process. Results show that the model predicts the experimental data accurately and it is further used for optimizing the separation process. The optimized process conditions consist of 1,2-dichloroethane as organic solvent, pH = 2.5 and the extractant concentration of 0.04 mol·kg–1. Under the optimum conditions, the enantioselectivity toward α-CPMA enantiomers is over 1.70 and performance factor is 0.07.
研究领域:
化学工程
·
分析化学
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产品关联
DOI
高影响因子
MICROCHEMICAL JOURNAL
·
2021
·
IF 4.821
Ya Liu,Li Jia
The realization of complete enantioseparation of a racemate in a single step is still a difficulty to be addressed. In this work, L-tryptophan (Trp) imprinted chitosan modified magnetic particles (Fe 3 O 4 @CS@MIP) were fabricated in a three-step process. The particles were spherical with an average diameter of 208.6 ± 9.6 nm. The thicknesses of CS and MIP layers were 3.9 ± 0.9 and 2.5 ± 1.4 nm, respectively. Fe 3 O 4 @CS@MIP possessed the chiral selectivity of CS and the stereoselective cavities of MIP. They were able to achieve the complete chiral separation of Trp racemate in aqueous solutions in a single step. The enantiomeric excess ( ee ) was almost 100%. The imprinting factor of this material for L-Trp was 5.75. Furthermore, Fe 3 O 4 @CS@MIP prepared using S-mandelic acid (S-MA) as a template also exhibited enantioselectivity toward S-MA with an ee value of 30%. The results demonstrate that the strategy for the preparation of chiral adsorbents has great potential in enantioseparation.
研究领域:
分析化学
·
材料科学
·
手性分离技术
✓ 已验证
产品关联
DOI
高影响因子
Drug Metabolism and Pharmacokinetics
·
2019
·
IF 1.874
Yang Zhang,Chen Su,Jinxiu Lei,Lu Chen,Haihong Hu,Su Zeng,Lushan Yu
Mandelic acid (MA) is generally used as a biomarker of the exposure of styrene , which is classified as a class of hazardous environmental pollutants, and also used as an important chiral intermediate in pharmaceutical industry. The previous studies have found the excretion of phenylglyoxylic acid (PGA) in human and rat, a metabolite of MA, was mainly from S- MA rather than R -MA. The metabolic mechanism, however, is not clear. In order to explore the possible metabolic mechanism, the enzyme types involved in the stereoselectivity metabolism of MA were firstly studied, and then human and rat long-chain 2-hydroxy-acid oxidase 2 (HAO2) were recombinantly expressed to study the metabolic profiles of S- MA and its analogues. The results indicated that HAO2 might catalyze the stereoselectivity metabolism of S- MA in rats. Human HAO2 ( h HAO2) and rat HAO2 ( r HAO2) isozymes β 1 and β 2 were successfully cloned and expressed with high purity and good enzyme activities. The enzyme kinetic profiles of these enzymes were different for S- MA and analogues. The order of catalytic efficiency for h HAO2 and r HAO2, however, was reverse. It might be relevance to the difference in active amino acid residues and loop 4 in human and rat L-2-hydroxy acid oxidase isozyme B crystal structures.
研究领域:
环境科学
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生物化学
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毒理学
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药物化学
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产品关联
DOI
PubMed
高影响因子
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