18875-34-8Relevant articles and documents
Purification, characterization and N-terminal sequence analysis of betel leaf (Piper betle) invertase
Hossain, Md. Murad,Pervin, Farzana,Absar, Nurul
, p. 389 - 397 (2011)
The present study is the first report describing the purification, enzymatic properties and N-terminal amino acid sequence of a native invertase in betel leaf. The invertase was purified as a monomeric glycoprotein of molecular mass (Mr) 68 kDa. The enzyme was capable to attack β-fructofuranoside linkages from the fructose end of sucrose, raffinose and stachyose indicating it as an authentic β-D-fructofurano-sidase with high specificity for sucrose (Km 4.83 mM). The maximum activity was detected at pH 5.2 and 37 °C. Glucose and fructose showed typical inhibitory effect on the enzyme activity where as lectin was found to be effective activators of the enzyme. Significant inhibition by heavy metal ion Hg2+ and sulf-hydryl group modifying agents suggesting that free sulfhydryl group containing amino acid, cysteine is necessary for the catalytic activity of the invertase. A BLAST search of the N-terminal amino acid sequence of betel leaf invertase showed significant homology with the homologous invertases in database.
Isomerization of glucose to fructose catalyzed by lithium bromide in water
Yoo, Chang Geun,Li, Ning,Swannell, Melanie,Pan, Xuejun
, p. 4402 - 4411 (2017)
This study demonstrated that glucose could be isomerized to fructose in the concentrated aqueous solution of lithium bromide (LiBr) under mild conditions. The isomerization mechanisms were studied via isotopic labeling experiments. It was found that both the cation (Li+) and the anion (Br-) in the system catalyzed the isomerization of glucose to fructose. Br- catalyzed the isomerization through the proton transfer mechanism via an enediol intermediate, while Li+ did it through an intramolecular hydride shift mechanism from C2 to C1. The estimation using quantitative 13C-NMR analysis indicated that Br- catalyzed approximately 85% of the isomerization, while Li+ was responsible for the remaining 15%. The results indicated that 31% of the fructose was produced from glucose in LiBr trihydrate at 120 °C for 15 min. The outcomes of this study provided not only a better understanding of and insights into the sugar transformations in the LiBr solution but also an alternative approach to produce fructose from glucose.
Integrated chemo-enzymatic production of 5-hydroxymethylfurfural from glucose
Simeonov, Svilen P.,Coelho, Jaime A. S.,Afonso, Carlos A. M.
, p. 997 - 1000 (2013)
Sweets for my sweet: The production and isolation of 5- hydroxymethylfurfural (HMF) in high yield and purity is demonstrated by using a combination of glucose-fructose isomerization with sweetzyme in wet tetraethylammonium bromide (TEAB) and clean fructose dehydration to HMF catalyzed by using HNO3 under moderate conditions, which allow the reuse of any unreacted glucose and TEAB. Copyright
Biochemical characterization of a novel glucose isomerase from Anoxybacillus gonensis G2T that displays a high level of activity and thermal stability
Karaoglu, Hakan,Yanmis, Derya,Sal, Fulya Ay,Celik, Ayhan,Canakci, Sabriye,Belduz, Ali Osman
, p. 215 - 224 (2013)
In the continuing search for novel enzymes suitable for the production of high fructose corn syrup (HFCS), a new glucose isomerase (GI) from the thermophile Anoxybacillus gonensis G2T is described. The gene encoding this GI (AgoG2GI) was cloned and then engineered for heterologous expression in Escherichia coli. The recombinant enzyme was purified from the heat treated cell-free extract by anion exchange chromatography followed by hydrophobic interaction chromatography. The purified enzyme showed optimal activity at 85 C and pH 6.5. The steady state parameters of Km and kcat with d-glucose were found to be 146.08 ± 9.50 mM and 36.47 ± 2.01 (1/s), respectively. l-arabinose, d-ribose and d-mannose also served as substrates for the enzyme with comparable kinetic parameters. AgoG2GI requires the divalent cations of Co2+, Mn2+ and Mg2+ for its maximal activity and thermostability. The results reported here are indicative of a new GI with desirable kinetics and stability parameters for the efficient production of HFCS at industrial scale.
Anti-cariogenic Characteristics of Rubusoside
Kim, Jeesoo,Nguyen, Thi Thanh Hanh,Jin, Juhui,Septiana, Iis,Son, Gyu-Min,Lee, Gang-Hee,Jung, You-Jin,Qureshi, Dilshad,Mok, Il Kyoon,Pal, Kunal,Yang, Soo-Yeon,Kim, Seong-Bo,Kim, Doman
, p. 282 - 287 (2019)
Streptococcus mutans plays an important role in the development of dental caries in humans by synthesizing adhesive insoluble glucans from sucrose by mutansucrase activity. To explore the anti-cariogenic characteristics of rubusoside (Ru), a natural sweetener component in Rubus suavissimus S. Lee (Rosaceae), we investigated the inhibitory effect of Ru against the activity of mutansucrase and the growth of Streptococcus mutans. Ru (50 mM) showed 97% inhibitory activity against 0.1 U/mL mutansucrase of S. mutans with 500 mM sucrose. It showed competitive inhibition with a Ki value of 1.1 ± 0.2 mM and IC50 of 2.3 mM. Its inhibition activity was due to hydrophobic and hydrogen bonding interactions based on molecular docking analysis. Ru inhibited the growth of S. mutans as a bacteriostatic agent, with MIC and MBC values of 6 mM and 8 mM, respectively. In addition, Ru showed synergistic anti-bacterial activity when it was combined with curcumin. Therefore, Ru is a natural anti-cariogenic agent with anti-mutansucrase activity and antimicrobial activity against S. mutans.
Efficient biotransformation of D-fructose to D-mannose by a thermostable D-lyxose isomerase from Thermosediminibacter oceani
Yu, Lina,Zhang, Wenli,Zhang, Tao,Jiang, Bo,Mu, Wanmeng
, p. 2026 - 2033 (2016)
D-Mannose has prebiotic effect and potential medical application. Besides, it can be used as substrate to produce mannitol, a functional polyol widely used in food industry. As this result, it has attracted many researchers’ attention. In this work, a thermostable D-mannose-producing D-lyxose isomerase (D-LI) was characterized from a hyperthermophile, Thermosediminibacter oceani. The recombinant D-LI could be remarkably activated by Mn2+. It displayed maximal activity in presence of 1 mM Mn2+ at pH 6.5 and 65 °C, and was determined to be highly thermostable at 80 °C. The half-life was calculated to be 5.64, 2.82, 0.77, and 0.2 h at 70, 75, 80, and 85 °C, respectively. The enzyme showed the optimum activity using D-lyxose as substrate and could also effectively catalyze the isomerization between D-fructose and D-mannose. Under optimum conditions, 101.6 g/L D-mannose was produced from 400 g/L D-fructose after reaction for 9 h, giving a conversion yield of 25.4%.
Simple preparation method for Mg–Al hydrotalcites as base catalysts
Lee, Gihoon,Kang, Ji Yeon,Yan, Ning,Suh, Young-Woong,Jung, Ji Chul
, p. 347 - 355 (2016)
In this paper, we report a very simple preparation method for Mg–Al hydrotalcites (HTs) as base catalysts via the hydration of their corresponding metal oxides (MgO and Al2O3) without any particular controlled variables. We also propose a reasonable explanation for a series of reaction pathways in which Mg–Al HTs are formed from their metal oxides. The Mg–Al HTs were formed by the reaction of Mg2+ and Al(OH)4?, which resulted from the hydration of both metal oxides. The prepared Mg–Al HTs retained their unique properties, including their layered hydroxide structure and memory effect and showed considerable catalytic activity in the isomerization of glucose to fructose. Consequently, this simple hydration of both metal oxides successfully synthesized Mg–Al HTs, which can be used as base catalysts or as catalyst precursors for calcined HTs in various base-catalyzed reactions.
Sorbitol dehydrogenase of Aspergillus niger, SdhA, is part of the oxido-reductive d-galactose pathway and essential for d-sorbitol catabolism
Koivistoinen, Outi M.,Richard, Peter,Penttilae, Merja,Ruohonen, Laura,Mojzita, Dominik
, p. 378 - 383 (2012)
In filamentous fungi d-galactose can be catabolised through the oxido-reductive and/or the Leloir pathway. In the oxido-reductive pathway d-galactose is converted to d-fructose in a series of steps where the last step is the oxidation of d-sorbitol by an NAD-dependent dehydrogenase. We identified a sorbitol dehydrogenase gene, sdhA (JGI53356), in Aspergillus niger encoding a medium chain dehydrogenase which is involved in d-galactose and d-sorbitol catabolism. The gene is upregulated in the presence of d-galactose, galactitol and d-sorbitol. An sdhA deletion strain showed reduced growth on galactitol and growth on d-sorbitol was completely abolished. The purified enzyme converted d-sorbitol to d-fructose with Km of 50 ± 5 mM and v max of 80 ± 10 U/mg.
Synergy of boric acid and added salts in the catalytic dehydration of hexoses to 5-hydroxymethylfurfural in water
Hansen, Thomas S.,Mielby, Jerrik,Riisager, Anders
, p. 109 - 114 (2011)
In combination with various salts boric acid, B(OH)3, was shown to be an efficient, weak Lewis acid catalyst in the aqueous dehydration of fructose to 5-hydroxymethylfurfural (HMF) due to strong complexation between the boron atom and the hexoses. In the dehydration of a highly concentrated aqueous fructose solution (30 wt%), a HMF yield of 60% was achieved at 92% fructose conversion and a HMF selectivity of 65% with 100 g L-1 B(OH) 3 and 50 g L-1 sodium chloride in the aqueous phase and methyl-isobutylketone (MIBK) as extracting solvent. Furthermore, the dehydration of glucose resulted in a yield of 14% HMF at 41% glucose conversion after 5 h at similar conditions. These results are highly competitive with currently reported aqueous HMF dehydration systems. In combination with the non-corrosive and non-toxic nature of the boric acid, compared to other well known homogeneous catalysts applicable for the dehydration process (e.g., H2SO 4 and HCl), clearly, the boric acid-salt mixture is a very attractive catalyst system.
Isomerization of glucose at hydrothermal condition with TiO2, ZrO2, CaO-doped ZrO2 or TiO2-doped ZrO2
Kitajima, Haruyuki,Higashino, Yoshimasa,Matsuda, Shiho,Zhong, Heng,Watanabe, Masaru,Aida, Taku M.,Smith, Richard Lee
, p. 67 - 72 (2016)
Catalytic activity of TiO2, ZrO2 and ZrO2 solid solutions (with CaO or TiO2) for the isomerization of glucose into fructose under hydrothermal conditions (120-180 °C for 5-15 min reaction time) was evaluated by experimental kinetic studies and surface acidity-basicity measurements. Kinetic studies were conducted with batch reactors heated by microwave. Under hydrothermal conditions regardless of the temperature, fructose yield was always below 10% and fructose selectivity was rapidly decreased with increasing glucose conversion. By adding 10 mM NaOH, fructose yield reached 20% at 160 °C for 5 min. In the presence of TiO2, fructose yield and selectivity were similar (160 °C, 47% of glucose conversion and 14% fructose yield). ZrO2 showed higher catalytic activity (160 °C, 63% glucose conversion and 21% fructose yield) compared with TiO2. The catalytic activity of TiO2 doped ZrO2 was between TiO2 and ZrO2. To increase the basicity of ZrO2, CaO was doped into the ZrO2 matrix. For experiments with the 24 wt% CaO doped ZrO2, fructose selectivity was higher than 70% even at 30% glucose conversion at 160 °C for 15 min. For systematical understanding catalytic activity of the metal oxides used, acidity and basicity of the catalysts were measured by temperature programmed desorption (TPD) using either CO2 or NH3. It was found that basicity on the surface increased with increasing the amount of CaO in the ZrO2 solid solution while acidity increased with amounts of TiO2. For a simple network model of glucose reactions, rate constants were fitted to the data assuming a simple network model and they were completed with the acid-base properties of TiO2, ZrO2 and CaO doped and TiO2 doped ZrO2. As a result, the reactivity was found to be correlated with the ratio of the base to acid sites on the surface and fructose formation was linearly proportional to the base/acid mole ratio on the surface of the catalysts.
