Journal of Molecular Catalysis B-enzymatic最新文献

{"title":"Peroxidase activity enhancement of myoglobin by two cooperative distal histidines and a channel to the heme pocket","authors":"Lei-Bin Wu ,&nbsp;Ke-Jie Du ,&nbsp;Chang-Ming Nie ,&nbsp;Shu-Qin Gao ,&nbsp;Ge-Bo Wen ,&nbsp;Xiangshi Tan ,&nbsp;Ying-Wu Lin","doi":"10.1016/j.molcatb.2016.08.018","DOIUrl":"10.1016/j.molcatb.2016.08.018","url":null,"abstract":"<div><p>To reveal the structure-function relationship of heme proteins, and to provide clues for creating artificial heme proteins with improved functions, we here use myoglobin (Mb) as a model protein, and report that its peroxidase activity can be enhanced by construction of two distal histidines and a channel to the heme pocket. It showed that in addition to a single distal histidine with a suitable distance to the heme iron (Phe43 to His43 mutation), a second distal histidine (Leu29 to His29 mutation) can work cooperatively to increase the turnover number, mimicking the role of well-known His-Arg pair in native peroxidases. Moreover, a channel created to the heme pocket by removal of the native His64 gate (His64 to Ala64 mutation) was shown to facilitate the binding of substrate, resulting in enhanced catalytic efficiency for the triple mutant L29H/F43H/H64A<!--> <!-->Mb, which is beyond the addition of both double mutants, L29H/H64A Mb and F43H/H64A<!--> <!-->Mb. These results provide valuable information for elucidating the structure-function relationship of heme proteins. In addition, this study provides clues for design of artificial heme proteins, and the strategy of creating a channel to the heme active center is expected be extended to design of other artificial enzymes with improved catalytic performance.</p></div>","PeriodicalId":16416,"journal":{"name":"Journal of Molecular Catalysis B-enzymatic","volume":"134 ","pages":"Pages 367-371"},"PeriodicalIF":0.0,"publicationDate":"2016-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.molcatb.2016.08.018","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88219308","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":"Oxidative biotransformations of phenol substrates catalysed by toluene dioxygenase: A molecular docking study","authors":"Patrick Höring ,&nbsp;Kyle Rothschild-Mancinelli ,&nbsp;Narain D. Sharma ,&nbsp;Derek R. Boyd ,&nbsp;Christopher C.R. Allen","doi":"10.1016/j.molcatb.2016.10.013","DOIUrl":"10.1016/j.molcatb.2016.10.013","url":null,"abstract":"<div><p>Toluene dioxygenase-catalysed (TDO) oxidation converts substituted phenol substrates into catechols, hydroquinones, and chiral cyclohexenone <em>cis</em>-diol products. The ratio between the isolated products varied widely even between similar substrates, e.g. <em>o</em>-cresol, <em>m</em>-cresol and <em>p</em>-cresol. These differences are caused by different binding interactions within the active site of TDO. This study provides insight into the binding interactions by molecular docking using AutoDock tools. The nature of binding of phenolic substrates was of major interest, in order to explain the observed regio- and stereo-selectiviy of product formation. The ellipse-shaped binding pocket of TDO consists of a polar and a hydrophobic region, limiting the possible substrate orientations. The phenolic hydroxyl group was preferentially hydrogen bonded with Gln-215 and His-311 in the active site. In some cases, a hydrogen bond was formed with other amino acids, <em>e.g.</em> Asp-219 and Met-220, instead. The position and type of the substituent on the phenol ring influences the formation of transient intermediates, and thus the nature and stability of the major isolated product.</p></div>","PeriodicalId":16416,"journal":{"name":"Journal of Molecular Catalysis B-enzymatic","volume":"134 ","pages":"Pages 396-406"},"PeriodicalIF":0.0,"publicationDate":"2016-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.molcatb.2016.10.013","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85560287","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":"The synergism of hot water pretreatment and enzymatic hydrolysis in depolymerization of lignocellulosic content of palm kernel cake","authors":"Shuofu Mi ,&nbsp;Hongqiang Li ,&nbsp;Shuying Li ,&nbsp;Yejun Han","doi":"10.1016/j.molcatb.2016.09.004","DOIUrl":"10.1016/j.molcatb.2016.09.004","url":null,"abstract":"<div><p>Palm kernel cake (PKC), mainly composed of mannan, lignin and protein, is abundant renewable resource with commercial value. To develop clean and efficient way for PKC refinery, the method based on the synergism of hot water pretreatment (HWP), steam pretreatment (SP) and enzymatic hydrolysis were developed. HWP of 180<!--> <!-->°C, 20<!--> <!-->min and SP of 121<!--> <!-->°C, 20<!--> <!-->min showed similar performance for sugar release from PKC. The main saccharides produced from PKC by HWP and SP were mannose and manno-oligosaccharides, while no furfural formed. The surface structure analyzed by SEM showed that HWP enhanced the microporosity of PKC, and the accessibility of which was increased thereafter. When HWP pretreated PKC was further hydrolyzed with enzyme cocktail (cellulase, xylanase, endo-mannanase), 45% of PKC was solubilized compared with the control. The manno-oligosaccharides produced by HWP and SP were converted to mannose and mannobiose by endo-mannanase. The results suggested that both HWP and SP promote enzymatic hydrolysis of PKC by releasing oligosaccharides and enhancing microporosity, and the synergism of which was effective for PKC decomposition.</p></div>","PeriodicalId":16416,"journal":{"name":"Journal of Molecular Catalysis B-enzymatic","volume":"134 ","pages":"Pages 37-42"},"PeriodicalIF":0.0,"publicationDate":"2016-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.molcatb.2016.09.004","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85568662","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":"Wickerhamomyces subpelliculosus as whole-cell biocatalyst for stereoselective bioreduction of ketones","authors":"Viktória Bódai ,&nbsp;László Nagy-Győr ,&nbsp;Róbert Örkényi ,&nbsp;Zsófia Molnár ,&nbsp;Szabolcs Kohári ,&nbsp;Balázs Erdélyi ,&nbsp;Zsuzsanna Nagymáté ,&nbsp;Csaba Romsics ,&nbsp;Csaba Paizs ,&nbsp;László Poppe ,&nbsp;Gábor Hornyánszky","doi":"10.1016/j.molcatb.2016.11.003","DOIUrl":"https://doi.org/10.1016/j.molcatb.2016.11.003","url":null,"abstract":"<div><p>Newly isolated strains of <em>Wickerhamomyces subpelliculosus</em> were recognized as excellent whole-cell biocatalyst for bioreduction of various ketones. The biocatalytic properties of the new strains were demonstrated in this study by stereoselective bioreduction of acetophenone <strong>1a</strong>, 2-heptanone <strong>1b</strong>, phenylacetone <strong>1c</strong>, 3,4-dimethoxyphenylacetone <strong>1d</strong> and 1-cyclopropyl-2-(2-methoxy-4-nitrophenoxy)ethanone <strong>1e</strong>. Our study is the first report on application of <em>W. subpelliculosus</em> as whole-cell biocatalyst for stereoselective bioreduction of prochiral ketones. In these processes, both the freshly harvested cell paste and the lyophilized cell powder were tested as biocatalyst using glucose or 2-propanol at various concentrations as cosubstrates for cofactor regeneration. The newly isolated strains of <em>W. subpelliculosus</em> showed diverse characteristics, including optimal pH, temperature and organic solvent tolerance. Bioreductions of phenylacetone <strong>1c</strong> applying glucose as cosubstrate under various mild conditions resulted (<em>S</em>)-1-phenylpropanol [(<em>S</em>)-<strong>2c</strong>] in good to excellent conversion (<em>c</em> <!-->=<!--> <!-->63.4%–99.9%) with excellent enantiomeric excess [<em>ee</em>_{(<em>S</em>)-<strong>2c</strong>} <!-->=<!--> <!-->98.7%–99.8%].</p></div>","PeriodicalId":16416,"journal":{"name":"Journal of Molecular Catalysis B-enzymatic","volume":"134 ","pages":"Pages 206-214"},"PeriodicalIF":0.0,"publicationDate":"2016-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.molcatb.2016.11.003","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91658154","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":"Recycling Rhizopus oryzae resting cells as biocatalyst to prepare near eutectic palmitic-stearic acid mixtures from non-edible fat","authors":"Pau Gallart-Sirvent ,&nbsp;Edinson Yara ,&nbsp;Gemma Villorbina ,&nbsp;Mercè Balcells ,&nbsp;Núria Sala ,&nbsp;Ramon Canela-Garayoa","doi":"10.1016/j.molcatb.2016.11.015","DOIUrl":"10.1016/j.molcatb.2016.11.015","url":null,"abstract":"<div><p>Here we studied non-edible fat waste as a starting material to prepare eutectic mixtures of biomaterials. Initially, the fat was hydrolyzed using water and <em>R. oryzae</em> resting cells. The hydrolysis was performed in organic solvent-free media and the degree of hydrolysis at 1<!--> <!-->h was 42% while hydrolytic values of 86% and 98% were achieved at 12 and 48<!--> <!-->h, respectively. To recover the resting cells, they were extracted in consecutive cycles with solvents or supercritical CO₂. Compared with solvents, supercritical CO₂ allowed the highest reuse. Hence, <em>R. oryzae</em> was used for 336<!--> <!-->h (7 reaction cycles), yielding 56.5<!--> <!-->g of free fatty acid/g biocatalyst. Crude glycerol was recovered, showing a purity of 66.0% and an ash and water content of 2.3% and 1.8%, respectively. The hydrolyzed fat was crystallized with several solvents to yield palmitic and stearic acid mixtures with melting point characteristics of eutectic mixtures. We recovered 76% to 90% of the palmitic and stearic acids present in the initial hydrolyzed animal fat, depending on the solvent. The palmitic:stearic acid ratios determined by GC-FID were similar to those reported for eutectic mixtures whit phase change materials properties, as were the melting points, which ranged from 51.5<!--> <!-->°C to 54.8<!--> <!-->°C.</p></div>","PeriodicalId":16416,"journal":{"name":"Journal of Molecular Catalysis B-enzymatic","volume":"134 ","pages":"Pages 172-177"},"PeriodicalIF":0.0,"publicationDate":"2016-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.molcatb.2016.11.015","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88179148","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":"Wickerhamomyces subpelliculosus as whole-cell biocatalyst for stereoselective bioreduction of ketones","authors":"Viktória Bódai, László Nagy-Győr, Róbert Örkényi, Z. Molnár, Szabolcs Kohári, Balázs Erdélyi, Zsuzsanna Nagymáté, C. Romsics, Csaba Paizs, L. Poppe, Gábor Hornyánszky","doi":"10.1016/J.MOLCATB.2016.11.003","DOIUrl":"https://doi.org/10.1016/J.MOLCATB.2016.11.003","url":null,"abstract":"","PeriodicalId":16416,"journal":{"name":"Journal of Molecular Catalysis B-enzymatic","volume":"15 1","pages":"206-214"},"PeriodicalIF":0.0,"publicationDate":"2016-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76085741","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":"Overexpression and characterization of CCD4 from Osmanthus fragrans and β-ionone biosynthesis from β-carotene in vitro","authors":"Xuesong Zhang ,&nbsp;Jianjun Pei ,&nbsp;Linguo Zhao ,&nbsp;Feng Tang ,&nbsp;Xianying Fang ,&nbsp;Jingcong Xie","doi":"10.1016/j.molcatb.2016.10.003","DOIUrl":"10.1016/j.molcatb.2016.10.003","url":null,"abstract":"<div><p>In this study, a recombinant carotenoid cleavage dioxygenase 4 was produced from <em>Osmanthus fragrans</em> by <em>E</em>. <em>coli</em> under different bacterial growth conditions and used to develop a biotechnological method for preparation of natural β-ionone from β-carotene. β-ionone was analyzed by HPLC and OfCCD4 activity was measured based on concentration change of β-ionone. At pH 8.0 and 35<!--> <!-->°C, the greatest activity of the purified recombinant protein was 14.3<!--> <!-->U/mg and the maximum concentration of β-ionone was 71.186<!--> <!-->mg/L within 1<!--> <!-->h. Both the enzyme activity and the concentration of β-ionone could increase by nearly 6 times with addition of 9% Triton X-100 and 2% liquid paraffin.</p></div>","PeriodicalId":16416,"journal":{"name":"Journal of Molecular Catalysis B-enzymatic","volume":"134 ","pages":"Pages 105-114"},"PeriodicalIF":0.0,"publicationDate":"2016-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.molcatb.2016.10.003","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77142136","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":"Karich Alexander ,&nbsp;Scheibner Katrin ,&nbsp;Ullrich René ,&nbsp;Hofrichter Martin","doi":"10.1016/j.molcatb.2016.10.014","DOIUrl":"https://doi.org/10.1016/j.molcatb.2016.10.014","url":null,"abstract":"<div><p>The catalase activity of three unspecific peroxygenases (UPOs) from the agaric basidiomycetes <em>Agrocybe aegerita</em>, <em>Coprinopsis cinerea</em> and <em>Marasmius rotula</em> was investigated. The study included analysis of pH dependency of the catalase reaction and H₂O₂ mediated enzyme inactivation as well as experiments on the influence of a second substrate on the course of catalase reaction. Apparent kinetic parameters (K_m, k_cat) for the catalase activity of UPOs were determined. Inactivation of UPOs by H₂O₂ is discussed with regard to O₂ production and remaining UPO activity. Furthermore formation of biliverdin as heme destruction product was demonstrated along with the formation of UPO compound III as a possible intermediate that forces the destruction process. Radical trapping experiments with methyl benzoate gave indication for the formation of hydroxyl radicals in the presence of excess H₂O₂. Eventually, a plausible pathway of heme destruction has been proposed, proceeding via UPO compound III and subsequent hydroxyl radical formation, which in turn may cause heme bleaching and verdoheme and biliverdin formation.</p></div>","PeriodicalId":16416,"journal":{"name":"Journal of Molecular Catalysis B-enzymatic","volume":"134 ","pages":"Pages 238-246"},"PeriodicalIF":0.0,"publicationDate":"2016-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.molcatb.2016.10.014","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90009190","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,&nbsp;Arun Goyal","doi":"10.1016/j.molcatb.2016.11.001","DOIUrl":"https://doi.org/10.1016/j.molcatb.2016.11.001","url":null,"abstract":"<div><p>Chondroitin lyases are therapeutically important enzymes. The functional aspects of a chondroitin AC lyase (<em>Ps</em>PL8A) from <em>Pedobacter saltans</em> DSM12145 were investigated. <em>Ps</em>PL8A was cloned in to pET28a(+) vector, expressed in <em>E. coli</em> BL-21(DE3) cells exhibited a molecular size of approximately, 77<!--> <!-->kDa. <em>Ps</em>PL8A displayed maximum activity with chondroitin 4-sulphate, C4S (489<!--> <!-->U<!--> <!-->mg⁻¹) followed by chondroitin 6-sulphate, C6S (214<!--> <!-->U<!--> <!-->mg⁻¹) and hyaluronic acid (43.2<!--> <!-->U<!--> <!-->mg⁻¹). <em>Ps</em>PL8A was maximally active at 39<!--> <!-->°C and pH 7.2. 100<!--> <!-->mM Na⁺ and 20<!--> <!-->mM Ca²⁺ ions enhanced the activity of <em>Ps</em>PL8A by 2-fold. The time dependent TLC analysis of <em>Ps</em>PL8A degraded products of C4S revealed the presence of higher degree of polymerization (DP) chondroitin sulphate (CS) oligosaccharides at initial stage, but after 1<!--> <!-->h, only ΔC4S disaccharide was produced as the major product. This result displayed that <em>Ps</em>PL8A follows initially a concomitant endo- and exo-lytic mode which finally shifted to exolytic mode of catalysis. The oligosaccharides released were identified as di-, hexa-, octa- and dodeca-saccharide by ESI–MS analysis. The ΔC4S disaccharide showed a peak at <em>m</em>/<em>z</em> 458 (ESI–MS) while in MS/MS mode it gave the peak at <em>m</em>/<em>z</em> 300. ESI–MS/MS, ¹H- and ¹³C- NMR analyses confirmed the structure of ΔC4S disaccharide product obtained after 24<!--> <!-->h reaction of C4S with <em>Ps</em>PL8A. The enzyme reported in present study can be used for cancer mitigation, spinal cord injury treatment and CS oligosaccharides production which act as anti-inflammatory agents. This is the first study reporting the cloning and expression of chondroitin AC lyase from <em>Pedobacter saltans</em> DSM 12145.</p></div>","PeriodicalId":16416,"journal":{"name":"Journal of Molecular Catalysis B-enzymatic","volume":"134 ","pages":"Pages 215-224"},"PeriodicalIF":0.0,"publicationDate":"2016-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.molcatb.2016.11.001","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90021899","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":"Efficient production of 5-aminovalerate from l-lysine by engineered Escherichia coli whole-cell biocatalysts","authors":"Xin Wang ,&nbsp;Peipei Cai ,&nbsp;Kequan Chen,&nbsp;Pingkai Ouyang","doi":"10.1016/j.molcatb.2016.10.008","DOIUrl":"10.1016/j.molcatb.2016.10.008","url":null,"abstract":"<div><p>In this study, we developed a whole-cell biocatalysis process for high-level conversion of <span>l</span>-lysine into 5-aminovalerate. To obtain the highly efficient whole-cell biocatalyst, five expression plasmids were constructed to optimize the expression of 5-aminovaleramide amidohydrolase and <span>l</span>-lysine 2-monooxygenase in <em>Escherichia coli</em>. The engineered strain BL-22A-RB-YB harboring plasmid pET22b-davA, pRSFDuet-davB and pACYCDuet-davB was correspondingly obtained. Subsequently, the effects of induction conditions, reaction temperature, metal ion additives, and cell permeability on the whole-cell biocatalyst system were evaluated to improve biocatalytic efficiency. Under optimized reaction conditions, 95.3<!--> <!-->g/L 5-aminovalerate was synthesized from 120<!--> <!-->g/L <span>l</span>-lysine with a yield of 99.1%, and 103.1<!--> <!-->g/L 5-aminovalerate was produced from 150<!--> <!-->g/L <span>l</span>-lysine with a molar yield of 85.7%. The 5-aminovalerate production was then further improved using a <span>l</span>-lysine fed-batch strategy, and a hyper 5-aminovalerate production of 240.7<!--> <!-->g/L was achieved within 28<!--> <!-->h with a yield of 86.8%. The whole-cell biocatalytic system described here demonstrated an environmentally friendly strategy for industrial production of 5-aminovalerate.</p></div>","PeriodicalId":16416,"journal":{"name":"Journal of Molecular Catalysis B-enzymatic","volume":"134 ","pages":"Pages 115-121"},"PeriodicalIF":0.0,"publicationDate":"2016-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.molcatb.2016.10.008","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75194067","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}