Journal of Molecular Catalysis B-enzymatic最新文献

{"title":"Isoquercitrin production from rutin catalyzed by naringinase under ultrasound irradiation","authors":"Dan Zhu ,&nbsp;An Gong ,&nbsp;Yan Xu ,&nbsp;D’assise Kinfack Tsabing ,&nbsp;Fuan Wu ,&nbsp;Jun Wang","doi":"10.1016/j.molcatb.2016.11.011","DOIUrl":"10.1016/j.molcatb.2016.11.011","url":null,"abstract":"<div><p>Isoquercitrin, a rare flavonol glycoside with wide biological activities and key synthetic intermediate for the production of enzymatically modified isoquercitrin (EMIQ), was conducted by naringinase-catalyzed conversion of rutin under ultrasound irradiation. The maximum yields were obtained to 98.35<!--> <!-->±<!--> <!-->3.13% and 95.20<!--> <!-->±<!--> <!-->2.52% under conventional heating and ultrasound irradiation, respectively. The optimal results under ultrasound irradiation were obtained under the following conditions: rutin concentration 0.8<!--> <!-->g/L, naringinase concentration 3000<!--> <!-->U/L, reaction temperature 40<!--> <!-->°C for 20<!--> <!-->min, which was more economical than that with conventional heating. The reaction time was reduced from 60<!--> <!-->min to 20<!--> <!-->min, and the apparent kinetic parameter (<em>V</em>_m/<em>K</em>_m) was increased 3.72-fold. The lower activity energy <em>E</em>_a under ultrasonic irradiation was 0.7-fold of that in an incubator reactor, which could easily initiate the enzymatic reaction. The association saturation constant <em>K</em>_a was 1.98-fold higher than that with conventional heating, showed a better affinity between rutin and naringinase detected by surface plasmon resonance (SPR) analysis. These results suggest that ultrasound irradiation can accelerate the enzymatic synthesis of isoquercitrin from rutin.</p></div>","PeriodicalId":16416,"journal":{"name":"Journal of Molecular Catalysis B-enzymatic","volume":"134 ","pages":"Pages 186-195"},"PeriodicalIF":0.0,"publicationDate":"2016-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.molcatb.2016.11.011","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84433214","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Laccase-catalyzed dimerization of glycosylated lignols","authors":"Ivan Bassanini ,&nbsp;Paolo Gavezzotti ,&nbsp;Daniela Monti ,&nbsp;Jana Krejzová ,&nbsp;Vladimír Křen ,&nbsp;Sergio Riva","doi":"10.1016/j.molcatb.2016.10.019","DOIUrl":"10.1016/j.molcatb.2016.10.019","url":null,"abstract":"<div><p>Phenylpropanoid glucosides (PPGs) are naturally occurring and bioactive phenolic derivatives, largely distributed in plants. In this work different PPGs have been chemically or enzymatically synthesized from the lignols coniferyl and <em>p</em>-coumaryl alcohols as substrates for a laccase-catalyzed oxidative coupling. The biooxidation of these PPGs has been investigated here and novel dihydrobenzofuran-based structurally modified analogues have been isolated and characterized. Specifically, the presence of a carbohydrate moiety increased the water solubility of these compounds and reduced the number of dimeric products, as pinoresinol-like structures could not be formed. Looking for a possible sugar-promoted stereochemical enrichment of the obtained diastereomeric mixtures of dimers, different carbohydrate moieties (<span>d</span>-glucose, <span>l</span>-glucose and the disaccharide rutinose) were considered and the respective d.e. values of the dimeric products were measured by ¹H NMR and HPLC. However, it was found that the sugar substituent had a minor effect on the stereochemical outcome of the radical coupling reactions, the best measured result being a d.e. value of 21%.</p></div>","PeriodicalId":16416,"journal":{"name":"Journal of Molecular Catalysis B-enzymatic","volume":"134 ","pages":"Pages 295-301"},"PeriodicalIF":0.0,"publicationDate":"2016-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.molcatb.2016.10.019","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84922113","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Exploring the catalase activity of unspecific peroxygenases and the mechanism of peroxide-dependent heme destruction","authors":"A. Karich, K. Scheibner, R. Ullrich, M. Hofrichter","doi":"10.1016/J.MOLCATB.2016.10.014","DOIUrl":"https://doi.org/10.1016/J.MOLCATB.2016.10.014","url":null,"abstract":"","PeriodicalId":16416,"journal":{"name":"Journal of Molecular Catalysis B-enzymatic","volume":"300 1","pages":"238-246"},"PeriodicalIF":0.0,"publicationDate":"2016-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77771605","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A new member of family 8 polysaccharide lyase chondroitin AC lyase (PsPL8A) from Pedobacter saltans displays endo- and exo-lytic catalysis","authors":"Aruna Rani, A. Goyal","doi":"10.1016/J.MOLCATB.2016.11.001","DOIUrl":"https://doi.org/10.1016/J.MOLCATB.2016.11.001","url":null,"abstract":"","PeriodicalId":16416,"journal":{"name":"Journal of Molecular Catalysis B-enzymatic","volume":"17 1","pages":"215-224"},"PeriodicalIF":0.0,"publicationDate":"2016-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73237468","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Nearly aqueous-like activity of lipoprotein lipase treated with glucose-headed surfactant in organic solvent","authors":"Yeonock Oh ,&nbsp;Yoon Kyung Choi ,&nbsp;Inyeol Yun,&nbsp;Eungyeong Lee,&nbsp;Kyungwoo Kim,&nbsp;Mahn-Joo Kim","doi":"10.1016/j.molcatb.2016.10.009","DOIUrl":"10.1016/j.molcatb.2016.10.009","url":null,"abstract":"<div><p>In this work, we explored the activation of a lipoprotein lipase from <em>Burkholderia species</em> by glucose-headed surfactants (GHSs) for enhancing its catalytic activity in organic solvent. Three GHSs were prepared and then tested as the additives for inducing the activation of lipoprotein lipase. The kinetic parameters of GHS-treated lipoprotein lipase were determined for the hydrolysis or alcoholysis of <em>p</em>-nitrophenyl acetate. It was found that GHS-treated lipoprotein lipase was 4 to 5 orders of magnitude more active than its native counterpart in organic solvent. Such a dramatic activity enhancement was largely the result of a huge increase in the turnover frequency <em>k</em>_cat. Surprisingly, the <em>k</em>_cat values in organic solvent were one order of magnitude greater than their aqueous counterparts. As a result, the <em>k</em>_cat/<em>K</em>_m of GHS-treated lipoprotein lipase in organic solvent became comparable to the aqueous level within one order of magnitude. We thus have demonstrated for the first time that a lipase can display nearly aqueous-like activity in organic solvent. As an illustrative application of GHS-treated lipoprotein lipase, we performed the dynamic kinetic resolution of two secondary alcohols, which provided the products of high enantiopurity (98–99%ee) with high yields (90–91%).</p></div>","PeriodicalId":16416,"journal":{"name":"Journal of Molecular Catalysis B-enzymatic","volume":"134 ","pages":"Pages 148-153"},"PeriodicalIF":0.0,"publicationDate":"2016-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.molcatb.2016.10.009","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88901018","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Biocatalytic epoxidation of α-pinene to oxy-derivatives over cross-linked lipase aggregates","authors":"Madalina Tudorache ,&nbsp;Andreea Gheorghe ,&nbsp;Ana S. Viana ,&nbsp;Vasile I. Parvulescu","doi":"10.1016/j.molcatb.2016.09.009","DOIUrl":"10.1016/j.molcatb.2016.09.009","url":null,"abstract":"<div><p>Lipase-based cross-linked aggregates were investigated for a non-specific reaction, <em>i.e.</em> the epoxidation of α-pinene to its oxygenated derivatives. The activity of the biocatalysts has been evaluated in a green context, <em>i.e</em>. ethyl acetate as both acetate-supplier and organic solvent with H₂O₂/UHP/TBHP as oxidant. Screening of the lipase sources indicated <em>Aspergillus niger</em> lipase as the most efficient biocatalyst for this reaction. Different immobilization protocols ((i) cross-linked enzyme aggregates (CLEA), (ii) cross-linked enzyme aggregates onto magnetic particles (CLEMPA) and (iii) covalent immobilized enzyme (CIE) onto magnetic particles (MP)) were evaluated considering the activity as main parameter. Thus, CLEA and CLEMPA afforded better epoxidation yields of α-pinene towards CIE. The investigated biocatalytic systems allowed to transform α-pinene into oxigenated derivatives with industrial and commercial applications (<em>e.g.</em> α-pinene oxide, camphene, pinanediol and camphonelic aldehyde). FTIR investigations on the biocatalysts revealed the effects of the immobilization protocol on the enzyme secondary-structure. Additionally, textural characterizations were performed by Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and Atomic Force Microscopy (AFM) analysis.</p></div>","PeriodicalId":16416,"journal":{"name":"Journal of Molecular Catalysis B-enzymatic","volume":"134 ","pages":"Pages 9-15"},"PeriodicalIF":0.0,"publicationDate":"2016-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.molcatb.2016.09.009","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80195203","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A simple approach to a vastly improved acetylcholinesterase activity and stability at elevated temperatures using magnetic microbeads and poly(N-(3-aminopropyl methacrylamide)) hydrogel supports","authors":"Lisa C. Shriver-Lake ,&nbsp;Paul T. Charles ,&nbsp;Andre A. Adams ,&nbsp;Jake Fontana ,&nbsp;Brett D. Martin","doi":"10.1016/j.molcatb.2016.09.007","DOIUrl":"10.1016/j.molcatb.2016.09.007","url":null,"abstract":"<div><p>The thermal stabilization of enzymes is a critical factor in the development and reliability of enzyme-based processes and functional materials. Using a simple amine coupling approach for enzyme immobilization onto magnetic microbeads, followed by encasement of the beads in a hydrogel, we demonstrate that the thermal stability of the enzyme acetylcholinesterase can be increased dramatically. For example, when free and microbead-immobilized enzyme (“EM Conjugate”) are incubated overnight in a dry state at 63<!--> <!-->°C (140<!--> <!-->°F), the catalytic efficiency (k_cat/K_m) of the latter is higher than the former by six orders of magnitude (a factor of 2.16<!--> <!-->×<!--> <!-->10⁶). This effect arises mostly through a ∼29,700-fold decrease in K_m experienced by the EM Conjugate, relative to that of the free enzyme. Encapsulation of the EM Conjugate in a hydrogel based on poly(N-(3-aminopropyl methacrylamide)), which contains a primary amine, affords the enzyme additional stability when incubated overnight at 63<!--> <!-->°C in an aqueous state. For example, its catalytic efficiency is four orders of magnitude higher than that of both the free enzyme (a factor of 4.34<!--> <!-->×<!--> <!-->10⁴) and that of the EM Conjugate alone (a factor of 1.78<!--> <!-->×<!--> <!-->10⁴) after all are incubated overnight at 63<!--> <!-->°C. The presence of the hydrogel also caused the Michaelis constant to decrease by 1.38<!--> <!-->×<!--> <!-->10⁴ relative to that of the EM Conjugate, reaching a value of 2.18<!--> <!-->×<!--> <!-->10⁻³ <!-->M. Thus the hydrogel enables the AChE substrate binding site to retain a significant amount of its natural affinity for the substrate, after heating. This effect may occur via ion-pairing by the primary amines in the hydrogel polymer repeat unit, which are protonated and positively-charged at the assay pH. To the best of our knowledge, this simple method for enzyme thermal stabilization is novel and has not yet been investigated.</p></div>","PeriodicalId":16416,"journal":{"name":"Journal of Molecular Catalysis B-enzymatic","volume":"134 ","pages":"Pages 61-69"},"PeriodicalIF":0.0,"publicationDate":"2016-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.molcatb.2016.09.007","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83991670","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Green routes towards industrial textile dyeing: A laccase based approach","authors":"Cinzia Pezzella ,&nbsp;Simona Giacobbe ,&nbsp;Valerio Guido Giacobelli ,&nbsp;Lucia Guarino ,&nbsp;Sibel Kylic ,&nbsp;Mehmet Sener ,&nbsp;Giovanni Sannia ,&nbsp;Alessandra Piscitelli","doi":"10.1016/j.molcatb.2016.11.016","DOIUrl":"10.1016/j.molcatb.2016.11.016","url":null,"abstract":"<div><p>Laccase-catalyzed synthesis of dye molecules represents a green choice to reduce the environmental footprint of conventional synthetic processes. Textile industry will benefit from this green technology since the synthesized dyes can be exploited to colour different fabrics.</p><p>This work describes the application of the <em>Pleurotus ostreatus</em> POXA1b laccase in polymeric dye synthesis using resorcinol and 2,5-diaminobenzenesulfonic acid (2,5-DABSA) as substrates. The potential of the resorcinol/2,5-DABSA coupling route was transferred to a chemical industry, Setaş Colour Center, by introducing a greener synthesis step within the process routinely used for textile dyeing. Dye synthesis was performed at different precursor ratios (1:1 and 1:10 2,5-DABSA: resorcinol) and their dyeing properties were compared on different fibres. The two mixtures of synthesized dyes proved to be effective on nylon and wool, with 1:10 ratio displaying the best performances in terms of dyeing efficiency and colour strength. Good and comparable end quality and “performances during use” were observed for nylon and wool coloured with both synthesized dyes.</p></div>","PeriodicalId":16416,"journal":{"name":"Journal of Molecular Catalysis B-enzymatic","volume":"134 ","pages":"Pages 274-279"},"PeriodicalIF":0.0,"publicationDate":"2016-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.molcatb.2016.11.016","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79056217","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evolved alkaline fungal laccase secreted by Saccharomyces cerevisiae as useful tool for the synthesis of C–N heteropolymeric dye","authors":"Ana I. Vicente ,&nbsp;Javier Viña-Gonzalez ,&nbsp;Paloma Santos-Moriano ,&nbsp;Carlos Marquez-Alvarez ,&nbsp;Antonio O. Ballesteros ,&nbsp;Miguel Alcalde","doi":"10.1016/j.molcatb.2016.10.004","DOIUrl":"10.1016/j.molcatb.2016.10.004","url":null,"abstract":"<div><p>Enzymatic production of C–N heteropolymeric dyes at alkaline pHs is an attractive process for the textile industry. In this work, we have designed a fungal laccase by directed evolution so that it may be used at alkaline pHs for the synthesis of C–N heteropolymeric dyes (C–N polydye) from catechol and 2,5-diaminobenzenesulfonic acid (2,5-DABSA). Firstly, several medium- and high-redox potential fungal laccases from previous laboratory evolution campaigns were benchmarked for the synthesis of the C–N polydye at pH 8.0, choosing an alkaline laccase mutant from <em>Myceliophthora thermophila</em> as the departure point for further engineering. Mutant libraries were then constructed, expressed in <em>Saccharomyces cerevisiae</em> and screened using a high-throughput colorimetric assay for the detection of the C–N polydye. By combining directed and focused molecular evolution, a novel, strongly expressed alkaline laccase variant was identified. This laccase was secreted at 37<!--> <!-->mg/L and its catalytic efficiency for the oxidation of catechol and 2,5-DABSA at pH 8.0 was enhanced 3.5-fold relative to that of the wild-type, promoting the synthesis of the C–N polydye at basic pHs. While the improved expression was mostly the result of accumulating mutations that favor the yeast’s codon usage together with the recovery of a secretion mutation, the enhanced C–N polydye synthetic activity of the mutant laccase was dependent on the alkaline mutations it inherited. Readily secreted, this laccase mutant would appear to be a valuable platform for organic synthesis at basic pHs.</p></div>","PeriodicalId":16416,"journal":{"name":"Journal of Molecular Catalysis B-enzymatic","volume":"134 ","pages":"Pages 323-330"},"PeriodicalIF":0.0,"publicationDate":"2016-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.molcatb.2016.10.004","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90380196","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"In vivo cytotoxicity, molecular docking and study of yeast alcohol dehydrogenase on polycarbazole-titanium dioxide nanocomposite","authors":"Mohammad Shakir ,&nbsp;Mohd. Shoeb Khan ,&nbsp;Umair Baig ,&nbsp;Md. Fazle Alam ,&nbsp;Hina Younus ,&nbsp;Mahboob Alam","doi":"10.1016/j.molcatb.2016.09.018","DOIUrl":"10.1016/j.molcatb.2016.09.018","url":null,"abstract":"<div><p>The present work deals with the synthesis of an electrically conductive polycarbazole-titanium dioxide (PCz/TiO₂-6%) nanocomposite employing facile <em>in-situ</em> oxidative polymerization of carbazole monomer. In order to immobilize the yeast alcohol dehydrogenase (YADH) enzyme, the polymerization reaction was done in the presence of TiO₂ (titanium dioxide). The pristine PCz and PCz/TiO₂-6% nanocomposites were fully characterized using Fourier transform infra-red spectroscopy, Scanning electron microscopy, Transmission electron microscopy, Thermogravimetric analysis and Differential thermal analysis. The studies revealed that the TiO₂ and YADH loading changes nanocomposite morphology in comparison to pristine PCz. YADH immobilization was efficient and successfully carried out on PCz and PCz/TiO₂-6% nanocomposite with a loading efficiency of 67.4% and 88.2% respectively. Immobilized YADH on the PCz/TiO₂-6% nanocomposite enhanced YADH stability, recycling efficiency, and residual activity, which makes it ideally suited for industrial applications. A total of four 3D molecular field descriptors or field points were used to characterize and define the necessary properties required for a molecule to bind into a specified active site, in a characteristic fashion. 3D molecular dynamics and a molecular docking simulation were employed to predict the modes of interactions of YADH with either PCz or PCz/TiO₂-6%. The <em>in vivo</em> cytotoxicity profiles of PCz and PCz/TiO₂-6% nanocomposite were obtained by lethality bioassay against brine shrimp nauplii.</p></div>","PeriodicalId":16416,"journal":{"name":"Journal of Molecular Catalysis B-enzymatic","volume":"134 ","pages":"Pages 79-88"},"PeriodicalIF":0.0,"publicationDate":"2016-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.molcatb.2016.09.018","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77773071","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}