MOLECULES
·
2022
·Vol. 27
·期 3
·1126
·
IF 4.927
Zhong-Lei Meng,Ru-Si Wen,Xiao-Rui Huang,Rong-Xiu Qin,Yi-Ming Hu,Yong-Hong Zhou
We report the use of five alpha-hydroxy acids (citric, tartaric, mandelic, lactic and glycolic acids) as catalysts in the synthesis of terpineol from alpha-pinene. The study found that the hydration rate of pinene was slow when only catalyzed by alpha-hydroxyl acids. Ternary composite catalysts, composed of AHAs, phosphoric acid, and acetic acid, had a good catalytic performance. The reaction step was hydrolysis of the intermediate terpinyl acetate, which yielded terpineol. The optimal reaction conditions were as follows: alpha-pinene, acetic acid, water, citric acid, and phosphoric acid, at a mass ratio of 1:2.5:1:(0.1–0.05):0.05, a reaction temperature of 70 °C, and a reaction time of 12–15 h. The conversion of alpha-pinene was 96%, the content of alpha-terpineol was 46.9%, and the selectivity of alpha-terpineol was 48.1%. In addition, the catalytic performance of monolayer graphene oxide and its composite catalyst with citric acid was studied, with acetic acid used as an additive.Keywords:pinene;terpineol;alpha-hydroxy acids;phosphoric acid;synthesis
研究领域:
有机化学
·
催化
·
材料科学
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产品关联
DOI
PubMed
高影响因子
SCIENTIA HORTICULTURAE
·
2024
·
IF 3.9
Canying Li,Shuran Zhang,Yueruxin Jin,Jiaqi Liu,Miao Wang,Yan Guo,Hengping Xu,Yonghong Ge
Acidity plays a crucial role in determining the sensory attributes of the majority of fresh fruit and vegetables. This study investigated the variations of organic acids metabolism and salicylic acid biosynthesis in Zaosu pears after postharvest phenyllactic acid dipping. Results elucidated that phenyllactic acid dipping improved the contents of malic, succinic, citric, and salicylic acid in Zaosu pears. Phenyllactic acid also improved the enzymatic activities and gene transcription levels of phosphoenolpyruvate carboxylase, mitochondrial citrate synthase, mitochondrial aconitase, and NADP-isocitrate dehydrogenase, whereas declined NADP-dependent malate (NADP-ME) and cytoplasmic aconitase activities as well as PbNADP-ME transcription level in pears. Moreover, the enzymatic activities and gene transcription levels of phenylalanine ammonia lyase and shikimate dehydrogenase as well as the gene transcription levels of 3-dehydroquinate synthase, d -arabino-heptulosonate-7-phosphate synthase, chorismate synthase, shikimate kinase, isochorismate synthase, 5-enolppyruvylshikimate-3-phosphate synthetase, avrPphB susceptible 3, enhanced pseudomonas susceptibility 1, enhanced disease susceptibility 5, and chorismate mutase in Zaosu pears were promoted by phenyllactic acid treatment. Taken together, phenyllactic acid can regulate the pivotal enzyme activity and gene transcription in organic acids metabolism and salicylic acid biosynthesis to sustain the flavor and freshness of Zaosu pears.
研究领域:
植物学
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食品科学
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分子生物学
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产品关联
DOI
高影响因子
HYDROMETALLURGY
·
2017
·
IF 2.605
Xiaobin Li,Leiting Shen,Qiusheng Zhou,Zhihong Peng,Guihua Liu,Tiangui Qi
Aiming to treat scheelite concentrate for producing ammonium paratungstate efficiently and cleanly, the conversion of scheelite to H 2 WO 4 and CaSO 4 ·nH 2 O in H 2 SO 4 solution was firstly studied in this work. The results show that H 2 SO 4 concentration, temperature, time, stirring speed, and particle size affect the conversion efficiency. Moreover, this work reveals that solid H 2 WO 4 layer on the surface of CaWO 4 particles forms and develops from thickness and looseness to thinness and denseness with increasing H 2 SO 4 concentration, and thus hinders the conversion of CaWO 4 to H 2 WO 4 , whereas CaSO 4 ·nH 2 O almost does not deposit in the layer. Meanwhile, H 2 WO 4 layer on CaWO 4 surface is resulted by isopolytungstate ions diffusion-tungstic acid deposition in diffusion layer. Additionally, the performance of separating H 2 WO 4 from CaSO 4 ·nH 2 O by leaching the converted product with aqueous ammonium carbonate solution was examined, showing that the converted product has an excellent leachability of tungsten in aqueous ammonium carbonate solution at ambient temperature with WO 3 leaching efficiency of about 99%. This work has the potential to develop a novel technique for tungsten extraction from scheelite concentrate under atmospheric pressure, bypassing the conversion of Na 2 WO 4 to (NH 4 ) 2 WO 4 .
研究领域:
冶金学
·
化学工程
✓ 已验证
DOI
高影响因子
JOURNAL OF BIOLOGICAL CHEMISTRY
·
2024
·
IF 4
Chunxiu Liu,Kailiang Ma,Li Jiang,Xumei Liu,Yang Tong,Sen Yang,Xinghua Jin,Yifeng Wei,Yan Zhang
The sulfite-reducing bacterium Bilophila wadsworthia , a common human intestinal pathobiont, is unique in its ability to metabolize a wide variety of sulfonates to generate sulfite as a terminal electron acceptor (TEA). The resulting formation of H 2 S is implicated in inflammation and colon cancer. l -cysteate, an oxidation product of l -cysteine, is among the sulfonates metabolized by B. wadsworthia , although the enzymes involved remain unknown. Here we report a pathway for l -cysteate dissimilation in B. wadsworthia RZATAU, involving isomerization of l -cysteate to d -cysteate by a cysteate racemase ( Bw CuyB), followed by cleavage into pyruvate, ammonia and sulfite by a d -cysteate sulfo-lyase ( Bw CuyA). The strong selectivity of Bw CuyA for d -cysteate over l -cysteate was rationalized by protein structural modeling. A homolog of Bw CuyA in the marine bacterium Silicibacter pomeroyi ( Sp CuyA) was previously reported to be a l -cysteate sulfo-lyase, but our experiments confirm that Sp CuyA too displays a strong selectivity for d -cysteate. Growth of B. wadsworthia with cysteate as the electron acceptor is accompanied by production of H 2 S and induction of Bw CuyA. Close homologs of Bw CuyA and Bw CuyB are present in diverse bacteria, including many sulfate- and sulfite-reducing bacteria, suggesting their involvement in cysteate degradation in different biological environments.
研究领域:
微生物学
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生物化学
·
分子生物学
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医学研究
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产品关联
DOI
PubMed
高影响因子
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2017
·Vol. 100
·期 10
·4491-4499
·
IF 2.841
Kangkang Yuan,Zhichao Yu,Chonghe Xu,Cong Feng,Xinzhu Gan,Xinqiang Wang,Luyi Zhu,Guanghui Zhang,Dong Xu
Acetic acid, lactic acid, and trifluoroacetic acid were used as complex agents for the preparation of dense barium zirconate fibers with electrospinning method. The formation of lactate when lactic acid was used as complex agent led to a mild decomposition process which was beneficial for the fabrication of dense barium zirconate fibers. High temperature stable intermediate phase of BaF 2 appeared when trifluoroacetic acid was used. The intermediate phase of BaF 2 was disadvantageous for pure and dense barium zirconate formation. While water vapor preheat treatment for BaF 2 contained fibers was an effective way for the fabrication of pure and dense barium zirconate fibers.
研究领域:
材料科学
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无机化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF CHEMICAL AND ENGINEERING DATA
·
2017
·
IF 2.323
Xiangji Liao,Xiuqing Li,Yujun Han,Jun Song,Yingjie Gao,Ao Yang,Yan Zhu,Weiping Luo
In this work, the solubilities of adipic acid and succinic acid in glutaric acid + cyclohexanone and glutaric acid + acetic acid mixtures were measured respectively by using the laser dynamic method under atmospheric pressure, in which the temperature ranged from 296.15 to 340.85 K and the mass fraction of glutaric acid in the binary solvent mixtures ranged from 0.00 to 0.30. The effects of glutaric acid on solubility of adipic acid and succinic acid have been discussed. It is found that the effects of glutaric acid on the solubility of adipic acid and succinic acid were negative and that with the increasing mass fraction of glutaric acid in the mixtures the solubilities of adipic acid and succinic acid would decrease. With the gradual increase of temperature, the measured solubility of adipic acid and succinic acid in glutaric acid + cyclohexanone and glutaric acid + acetic acid mixtures would increase at the constant proportion of solvent mixtures. Then the experimental data were well-correlated by the modified Apelblat equation and the modified nonrandom two-liquid (NRTL) activity coefficient models, in which the average relative deviation (ARD) were less than 2.50%, and the values of the solubility calculated showed good agreement with the experimental observation. The interaction parameters of AA and GA and SA and GA were determined first in this work.
研究领域:
化学工程
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物理化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MOLECULAR LIQUIDS
·
2023
·
IF 6
Chong Liang,Wei Zhao,Shangshang Ma,Dingkai Wang,Xutang Liu,Linyang Dong
To explore the effect of adding acidic ionic liquids (ILs) to the heteropoly acid/H 2 SO 4 catalytic system on the aerobic oxidation of lignite, acidic ILs functionalized with -SO 3 H were synthesized accordingly and mixed with H 5 PMo 10 V 2 O 40 (HPA-2) in various molar ratios. The optimum combination of HPA-2 and 1-methyl-3-(4-sulfobutyl) imidazolium (MIMBS) with molar ratio of 0.3 showed excellent performance for the catalytic oxidation of lignite, with the yields of carboxylic acids (CAs) (including benzene carboxylic acids, formic acid and acetic acid) reaching 326.21 ± 12.86 mg/g lignite, which considerably exceeded the 136.08 ± 6.23 mg/g lignite of pure HPA-2. Highest occupied molecular orbital energy of CAs calculated by Gaussian 09 on 6-31G(d) basis set and Hammett function analysis confirmed that the oxidative activity and acidity of the catalytic system could be moderately modulated by sulfonated ILs, thereby increasing the yield of CAs. In addition, the effect of H 2 SO 4 concentration on the oxidation of lignite was investigated via the HPA-2/H 2 SO 4 /MIMBS system with different molar ratios, and the results showed that CAs yield increased first and then decreased with increasing H 2 SO 4 concentration, but the concentration of H 2 SO 4 at the maximum yield of CAs was significantly reduced from 0.28 wt% to 0.14 wt% once MIMBS was added. A possible process for the catalytic oxidation of lignite by sulfonated ILs/HPA-2/H 2 SO 4 in aerobic aqueous solution is proposed, which generally involves the reactions of hydrolysis, oxidation and re-oxidation. Due to the good reproducibility, the robust homogeneous catalytic system of HPA-2/sulphonated ILs has the advantages of including increased yields of CAs and reduced H 2 SO 4 dosage, which will pave the way for the efficient utilization of lignite.
研究领域:
化学工程
·
能源化学
✓ 已验证
产品关联
DOI
高影响因子
Catalysis Science & Technology
·
2021
·Vol. 12
·期 2
·596-605
·
IF 6.119
Daofeng Huang,Siyue Chen,Sicong Ma,Xin Chen,Yuanhang Ren,Meiyin Wang,Lin Ye,Li Zhang,Xueying Chen,Zhi-Pan Liu,Bin Yue,Heyong He
Sulfated zirconia (SZ) plays an important role in solid acid catalysts. To understand the origin of the super acidity over the surface of sulfated zirconia, pure monoclinic and tetragonal phase zirconia and their sulfated counterparts (M-SZ and T-SZ, respectively) were prepared, and the acid properties of these samples were characterized by 31P MAS NMR using TMP as the probe molecule. In comparison with zirconia, stronger Lewis acid (LA) and Brønsted acid (BA) sites were generated over the SZ samples after sulfation. The density ratios of the newly generated LA and strong BA sites were found to be ca. 2.0 : 1.0 on M-SZ and ca. 1.8 : 1.0 on T-SZ. Based on this quantitative relationship between the newly generated LA and strong BA sites, the possible acid structures on the SZ surface with different crystal phases are established. After structural optimization and theoretical calculation, the super acid sites originating from the bisulfate ions on the monoclinic (001) plane and the tetragonal (111) plane are determined.
研究领域:
催化化学
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材料科学
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理论计算化学
✓ 已验证
产品关联
DOI
高影响因子
Asian Journal of Organic Chemistry
·
2017
·Vol. 6
·期 10
·1385-1389
·
IF 2.788
Kui Wang,Jian-Hua Cui,Si-Yang Xing,Xiao-Wei Ren
Graphical I recall you ! Highly selective recognition of acidic amino acids, such as glutamic acid and aspartic acid, by a positively charged calixpyridinium is reported. Highly selective recognition of acidic amino acids, such as glutamic acid and aspartic acid, by a positively charged calixpyridinium is reported. The complexation behavior of the calixpyridinium host towards a dipeptide containing the glutamic acid residue and a glutamic acid metabolite is also described.
研究领域:
生物化学
·
分子识别
·
有机化学
✓ 已验证
产品关联
DOI
高影响因子
Food Bioscience
·
2022
·
IF 5.318
Chang Liu,Yahui Guo,He Qian,Yuliang Cheng
Inulin can regulate the intestinal micro-ecological balance, but there are few studies on the changes of intestinal microbiota and its metabolites in vitro and vivo , SCFAs and amino acids in particular. In this study, the human fecal microbiota glycolysis model and a mouse model were used to study the mechanism of inulin on intestinal microecology. Combined with metabolism of microbiome and metabolome , the cross-synergism mechanism of inulin-micribiota-metabolites-metabolism was investigated. The results revealed that after inulin was fermented by human intestinal microbiota , the relative abundance of Lactobacillus , Bifidobacterium , Prevotella , Catenibacterium , and Agathobacter increased. In vivo , the concentration of SCFAs increased after inulin was fermented, and the abundance of Parabacteroides , Muribaculaceae and Alloprevotella increased. Both in vivo and in vitro experiments revealed that inulin can regulate the expression of 5 genes involved in Valine , leucine and isoleucine degradation. In addition, the metabolome results confirmed that Valine, leucine and isoleucine degradation, Tyrosine metabolism, and Synthesis and degradation of ketone bodies are regulatory pathways of inulin. More importantly, L−tryptophan, tyrosine, L−fucose, L−ornithine, D−fructose, D−erythrose, and pyruvic acid are hallmark metabolites of inulin metabolized by gut microbiota. The cross-synergism network greatly indicated the microbiota ( Streptococcus , Lactobacillus , Muribaculaceae), metabolites ( l -tryptophan, pyruvic acid), and metabolism (Lysine degradation, Tryptophan metabolism , Synthesis and degradation of ketone bodies) may be the key factors involved in the mechanisms regulating the in vitro and vivo effects of inulin.
研究领域:
微生物学
·
代谢组学
·
营养科学
·
胃肠病学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF BIOLOGICAL CHEMISTRY
·
2020
·Vol. 295
·期 19
·6425-6446
·
IF 4.238
Chengmeng Jin,Xiaobing Zhu,Hao Wu,Yuqi Wang,Xun Hu
Phosphoglycerate kinase 1 (PGK1) plays important roles in glycolysis, yet its forward reaction kinetics are unknown, and its role especially in regulating cancer cell glycolysis is unclear. Here, we developed an enzyme assay to measure the kinetic parameters of the PGK1-catalyzed forward reaction. The Km values for 1,3-bisphosphoglyceric acid (1,3-BPG, the forward reaction substrate) were 4.36 μm (yeast PGK1) and 6.86 μm (human PKG1). The Km values for 3-phosphoglycerate (3-PG, the reverse reaction substrate and a serine precursor) were 146 μm (yeast PGK1) and 186 μm (human PGK1). The Vmax of the forward reaction was about 3.5- and 5.8-fold higher than that of the reverse reaction for the human and yeast enzymes, respectively. Consistently, the intracellular steady-state concentrations of 3-PG were between 180 and 550 μm in cancer cells, providing a basis for glycolysis to shuttle 3-PG to the serine synthesis pathway. Using siRNA-mediated PGK1-specific knockdown in five cancer cell lines derived from different tissues, along with titration of PGK1 in a cell-free glycolysis system, we found that the perturbation of PGK1 had no effect or only marginal effects on the glucose consumption and lactate generation. The PGK1 knockdown increased the concentrations of fructose 1,6-bisphosphate, dihydroxyacetone phosphate, glyceraldehyde 3-phosphate, and 1,3-BPG in nearly equal proportions, controlled by the kinetic and thermodynamic states of glycolysis. We conclude that perturbation of PGK1 in cancer cells insignificantly affects the conversion of glucose to lactate in glycolysis.
研究领域:
生物化学
·
癌症生物学
·
细胞代谢
·
酶学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Bioanalysis
·
2015
·Vol. 7
·期 9
·
IF 3.003
Shirui Zheng,Zhiyuan Ma,Feifeng Song,Jianfeng Ye,Ruwei Wang,Meijuan Tu,Liping Li,Hui Zhou,Su Zeng,Huidi Jiang
Background: Deficiency or imbalance of unsaturated fatty acids will promote the pathogenesis of many diseases. In order to monitor the exposure of unsaturated fatty acids, the method based on LC–MS/MS was developed. Results: Standard calibration curves for α-linolenic acid, linoleic acid, palmitoleic acid and oleic acid were linear (r ≥0.99). The intra-and interbatch accuracy (RE%) ranged from -4.5 to 8.6%, while the intra- and interbatch precisions (RSD%) were ≤8.7%. The extraction recovery varied from 85.4 to 99.6%, and no obvious matrix effect was observed. Conclusion: The method offers a simple approach for measuring 4 unsaturated fatty acids in 1 μl rat plasma within 3.95 min.
研究领域:
分析化学
·
医学
·
营养学
✓ 已验证
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）