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Enzimas fibrolíticas e emurchecimento no controle de perdas da ensilagem e na digestão de nutrientes em bovinos alimentados com rações contendo silagem de capim Tanzânia.; Fibrolytic enzymes and wilting to control ensiling losses and nutrient digestion in bovine fed with Tanzania grass silage based rations.

Loures, Daniele Rebouças Santana
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 29/04/2004 Português
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Este trabalho teve por objetivo avaliar o efeito de enzimas fibrolíticas na degradação da parede celular do volumoso, quando aplicadas antes da ensilagem e no momento da alimentação do animal. No experimento I analisou-se o efeito do emurchecimento, da redução do tamanho de partículas e da adição de enzimas fibrolíticas (associadas ou não ao inoculante bacteriano Lactobacillus plantarum) na fermentação e nas perdas do processo de ensilagem de capim Tanzânia (Panicum maximum, Jacq. cv. Tanzânia). A forragem foi cortada aos 45 dias de crescimento vegetativo e armazenada em silos experimentais (50 L) durante 136 dias. Durante o período de armazenamento o efluente foi coletado e quantificado no 1o, 2o, 7o, 14o, 21o, 60o, 90o e 136o dias. A redução do tamanho de partícula não influenciou as perdas totais, embora o tamanho menor tenha contribuído para garantir maior estabilidade aeróbia da silagem. A taxa de recuperação e as perdas de MS por efluente e gases foram de 72, 5 e 23% nas silagens não-emurchecidas e de 80, 0 e 21% nas silagens emurchecidas, respectivamente. A adição de enzimas fibrolíticas associadas ou não ao inoculante bacteriano promoveu redução da fração fibrosa (FDN, FDA, celulose, hemicelulose)...

"Aplicação da bioinformática no estudo dos genes e enzimas envolvidos na síntese da goma fastidiana produzida pela xylella fastidiosa" ; "Bioinformatic applied in studies of the enzymes involved in the biosynthesis of the exopolysaccharide, fastidian gum, produced by Xylella Fastidiosa"

Muniz, João Renato Carvalho
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 25/04/2003 Português
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Xylella fastidiosa é uma bactéria Gram-negativa, limitada ao xilema das plantas e o agente causador de diversas doenças em importantes plantações como citros, videiras, mirta, amêndoa, arbustos e café. Em citros, X. fastidiosa causa a Clorose Variegada dos Citros (CVC) ou “amarelinho”. Nove enzimas (GumB, C, D, E, F, H, J, K e M) estão envolvidas nas etapas biossintéticas de um polissacarídeo extracelular (EPS), chamado de goma fastidiana, um dos mecanismos envolvidos na patogênese da bactéria. Essas enzimas catalisam reações de adição de açúcares, polimerização e exportação do EPS através da membrana da bactéria. No presente trabalho, ferramentas de bioinformática foram utilizadas para o estudo e entendimento da biossíntese da goma fastidiana. As nove enzimas foram estudadas quanto ao seu conteúdo de estrutura secundária, análise de hidrofobicidade e das regiões transmembrânicas, classificação quanto as suas funções. A construção de modelos estruturais para as enzimas Gums através de comparação por homologia seqüencial mostrou ser um processo impossível, devido a falta de moléculas homólogas com estruturas tridimensionais conhecidas. Por outro lado, métodos de reconhecimento de enovelamento mostraram bons resultados e comparações entre as estruturas secundárias das enzimas Gums foram calculadas com a utilização dos programas GenThreader e THREADER 3.3. Modelos tridimensionais para as enzimas GumB...

Ação das enzimas ligninolíticas produzidas por Aspergillus niger e Penicillium sp. em bagaço de cana-de-açúcar tratado quimicamente; The action of lignolytic enzymes produced by Aspergillus niger and Penicillium sp in chemically treated sugarcane bagasse

Fasanella, Cristiane Cipola
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 22/01/2009 Português
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A cana-de-açúcar é uma das matérias primas para a produção de açúcar e álcool. Durante o processo de produção, é gerado como subproduto (ou resíduo) o bagaço, que possui várias aplicações, entre elas a geração de energia, fertilizantes, produção de combustíveis e ração animal. O bagaço da cana-de-açúcar é composto principalmente por materiais lignocelulósicos, possuindo como constituintes principais a celulose, a hemicelulose e a lignina. A lignina é um dos materiais mais recalcitrantes na natureza e, conseqüentemente, dificulta o acesso de enzimas aos carboidratos fermentáveis, reduzindo a eficiência da degradação da celulose e da fermentação. Uma das vias de degradação da lignina ocorre através da ação de enzimas produzidas por fungos de degradação branca, marrom e macia. Essas enzimas são capazes de degradar e expor a celulose e a hemicelulose, que, por sua vez são prontamente utilizadas por outros microrganismos. Para que isso ocorra, esses fungos promovem um processo de oxidação de compostos fenólicos e não fenólicos da molécula de lignina por meio de enzimas ligninolíticas extracelulares entre elas a lacase e a manganês peroxidase (MnP), em baixa velocidade, porém com grande eficiência. O presente trabalho tem como objetivo avaliar diferentes tratamentos químicos alcalinos (NaOH e Ca(OH)2) e biológicos (Penicillium sp. e Aspergillus niger) por microscopia óptica...

Hide unhairing and characterization of commercial enzymes used in leather manufacture

Dettmer, Aline; Ayub, Marco Antônio Záchia; Gutterres, Mariliz
Fonte: Universidade Federal do Rio Grande do Sul Publicador: Universidade Federal do Rio Grande do Sul
Tipo: Artigo de Revista Científica Formato: application/pdf
Português
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The enzymatic treatment of hides in tannery processes is a promising technology. However, the reaction kinetics of commercial enzymes available to the leather industry are not fully understood and their activities have been mainly determined with model proteins such as casein as substrate, which are not of direct relevance for cattle hides. Therefore, it is important to determine their activities on collagen and keratin, the main proteins of skin, in order to use these enzymes in leather processing. This work describes the study of five proteases, used commercially in tanneries, to assess their ability to act upon collagen and keratin and to determine their unhairing. Results showed that all commercial enzymes tested had more activity on collagen than on keratin. Unhairing was also tested and four out of the five enzymes tested showed some unhairing activity. Optima of the temperature and pH of the enzymes were very similar for all five enzymes, with maximal activities around 55°C and pH 9 to 12, respectively.

Pectin and pectinases: Production, characterization and industrial application of microbial pectinolytic enzymes

Pedrolli, Danielle Biscaro; Monteiro, Alexandre Costa; Gomes, Eleni; Carmona, Eleonora Cano
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Revisão Formato: 9-18
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Pectinases are a big group of enzymes that break down pectic polysaccharides of plant tissues into simpler molecules like galacturonic acids. It has long been used to increase yields and clarity of fruit juices. Since pectic substances are a very complex macromolecule group, various pectinolytic enzymes are required to degrade it completely. These enzymes present differences in their cleavage mode and specificity being basically classified into two main groups that act on pectin smooth regions or on pectin hairy regions. Pectinases are one of the most widely distributed enzymes in bacteria, fungi and plants. This review describes the pectinolytic enzymes and their substrates, the microbial pectinase production and characterization, and the industrial application of these enzymes. © Pedrolli et al.; Licensee Bentham Open.

Application of high pressure homogenization technology in the modification on milk-clotting enzymes = : Aplicação da tecnologia de homogeneização à alta pressão na modificação de enzimas coagulantes do leite; Aplicação da tecnologia de homogeneização à alta pressão na modificação de enzimas coagulantes do leite

Bruno Ricardo de Castro Leite Júnior
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 27/02/2014 Português
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A homogeneização à alta pressão (HAP) é um processo capaz de alterar a conformação e funcionalidade de enzimas. Os objetivos deste trabalho foram: (i) avaliar a influência da HAP até 190 MPa nas atividades proteolítica e de coagulação do leite bem como na estabilidade de quatro enzimas coagulantes do leite, (ii) acompanhar o processo de coagulação por ensaios reológicos e (iii) avaliar o desenvolvimento dos géis por 24 horas por meio das análises de proteólise, sinérese, reologia e microscopia. As avaliações foram feitas comparando-se os resultados obtidos com as enzimas processadas e não processadas. O coalho de vitelo processado a 190 MPa apresentou redução de 52% na atividade proteolítica, aumento da taxa de coagulação do leite e gel formado mais consistente. A avaliação deste gel por 24h indicou a formação de uma rede proteica com menor proteólise, maior sinérese, maior consistência e menor porosidade. Após processamento a 150 MPa, o coalho de bovino adulto apresentou redução da atividade proteolítica, aumento da atividade e estabilidade de coagulação do leite, maior taxa de coagulação do leite e formação de gel com maior consistência. O gel se mostrou mais compacto, firme e com maior expulsão do soro da matriz proteica nas 24h em que foi avaliado. A protease fúngica do Rhizomucor miehei foi a enzima mais resistente ao processo de HAP...

Aplicação de técnicas de reconhecimento de padrões usando os descritores estruturais de proteínas da base de dados do software STING para discriminação do sítio catalítico de enzimas; Pattern recognition using structural protein descriptors from STING database to discriminate the active site of enzymes

José Augusto Salim
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 24/02/2015 Português
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As enzimas têm sua função determinada essencialmente por alguns resíduos específicos, denominados resíduos de aminoácidos catalíticos. A função de uma determinada proteína é mantida por milhares de anos de pressão seletiva que ocasionam a preservação de uma estrutura composta por padrões físicos, químicos e estruturais necessários para mantê-la. É frequente observar que enzimas quaisquer presentes em organismos distantemente relacionados exerçam exatamente a mesma função biológica e possuam o mesmo conjunto de resíduos de aminoácidos catalíticos, apesar de possuírem sequências proteicas muito dissimilares. Estes padrões que se conservaram por anos de evolução para manter a função das enzimas têm sido bastante estudados na literatura. Assim, o presente trabalho buscou identificar, dentre os descritores estruturais de proteínas (disponíveis na base de dados da plataforma Blue Star STING) aqueles de maior relevância para discriminar os resíduos de aminoácidos catalíticos dos não catalíticos, por meio do nanoambiente no qual estes se inserem. Buscou-se por modelos classificadores capazes de favorecerem uma interpretação de suas escolhas através de regras na forma SE-ENTÃO, compostas por descritores e seus respectivos valores. Regras foram extraídas para conjuntos de enzimas responsáveis pela catálise da mesma reação enzimática (mesma sub-subclasse EC)...

Mo and W bis-MGD enzymes: nitrate reductases and formate dehydrogenases

Moura, José J. G.; Brondino, Carlos D.; Trincão, José; Romão, Maria J.
Fonte: Springer Publicador: Springer
Tipo: Artigo de Revista Científica
Publicado em //2004 Português
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J Biol Inorg Chem (2004) 9: 791–799 DOI 10.1007/s00775-004-0573-9; Molybdenum and tungsten are second- and third-row transition elements, respectively, which are found in a mononuclear form in the active site of a diverse group of enzymes that generally catalyze oxygen atom transfer reactions. Mononuclear Mo-containing enzymes have been classified into three families: xanthine oxidase, DMSO reductase, and sulfite oxidase. The proteins of the DMSO reductase family present the widest diversity of properties among its members and our knowledge about this family was greatly broadened by the study of the enzymes nitrate reductase and formate dehydrogenase, obtained from different sources. We discuss in this review the information of the better characterized examples of these two types of Mo enzymes and W enzymes closely related to the members of the DMSO reductase family. We briefly summarize, also, the few cases reported so far for enzymes that can function either with Mo or W at their active site.

Parasite enzymes as a tool to investigate immune responses

Cesari,Italo M.; Bouty,Isabelle; Bout,Daniel; Noya,Belkisyolé Alarcón de; Hoebeke,Johan
Fonte: Instituto Oswaldo Cruz, Ministério da Saúde Publicador: Instituto Oswaldo Cruz, Ministério da Saúde
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/1992 Português
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Previous evidences reported by us and by other authors revealed the presence of IgG in sera of Schistosoma mansoni-infected patients to immunodominant antigens which are enzymes. Besides their immunological interest as possible inductors of protection, several of these enzume antigens might be also intersting markers of infection in antibody-detecting immunocapture assays which use the intrinsic catalytic property of these antigens. It was thus thought important to define some enzymatic and immunological characteristics of these molecules to better exploit their use as antigens. Four different enzymes from adult worms were partially characterized in their biochemical properties and susceptibility to react with antibodies of infected patients, namely alkaline phosphatase (AKP, Mg*+, pH 9.5), type I phosphodiesterase (PDE, pH 9.5), cysteine proteinase (CP, dithiothreitol, pH 5.5) and N-acetyl-ß-D-glucosaminidase (NAG, pH 5.5). The AKP and PDE are distinct tegumental membrane-bound enzymes whereas CP and NAG are soluble acid enzymes. Antibodies in infected human sera differed in their capacity to react with and to inhibit these enzyme antigens. Possibly, the specificity of the antibodies related to the extent of homology between the parasite and the host enzyme might be in part responsible for the above differences. The results are also discussed in view of the possible functional importance of these enzymes.

Hide unhairing and characterization of commercial enzymes used in leather manufacture

Dettmer,A; Ayub,M. A. Z; Gutterres,M
Fonte: Brazilian Society of Chemical Engineering Publicador: Brazilian Society of Chemical Engineering
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/09/2011 Português
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The enzymatic treatment of hides in tannery processes is a promising technology. However, the reaction kinetics of commercial enzymes available to the leather industry are not fully understood and their activities have been mainly determined with model proteins such as casein as substrate, which are not of direct relevance for cattle hides. Therefore, it is important to determine their activities on collagen and keratin, the main proteins of skin, in order to use these enzymes in leather processing. This work describes the study of five proteases, used commercially in tanneries, to assess their ability to act upon collagen and keratin and to determine their unhairing. Results showed that all commercial enzymes tested had more activity on collagen than on keratin. Unhairing was also tested and four out of the five enzymes tested showed some unhairing activity. Optima of the temperature and pH of the enzymes were very similar for all five enzymes, with maximal activities around 55ºC and pH 9 to 12, respectively.

Digestibility of the cottonseed meal with or without addition of protease and phytase enzymes in swine diet

Lorena-Rezende,Izaura Maria Barros de; Dutra Junior,Wilson Moreira; Rezende,Fábio Monteiro de; Palhares,Liliane Olímpio; Ludke,Maria do Carmo Mohaupt Marques; Rabello,Carlos Bôa-Viagem
Fonte: Editora da Universidade Estadual de Maringá - EDUEM Publicador: Editora da Universidade Estadual de Maringá - EDUEM
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/09/2012 Português
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This study evaluated the digestibility of cottonseed meal with or without addition of enzymes (phytase and protease) for growing pigs. It was used 18 barrows, housed in metabolism cages, distributed in a completely randomized design, standardizing body weight (bw) with average of 25.8 ± 3.6 kg, with three treatments and six repetitions. The treatments consisted of a reference diet based on corn and soybean meal, the second treatment with replacement of 30% of the reference diet by cottonseed meal without enzymes, and the third with 30% of the reference diet replaced by cottonseed meal with added enzymes. Was determined the digestible protein, digestible energy, digestibility of dry matter, energy and protein. It was also registered the balance of nitrogen and phosphorus. The use of cottonseed meal with the addition of enzymes in diets for growing pigs has no effect on the digestibility of dry matter, gross energy and crude protein, but improved the absorption of phosphorus, consequently reducing its excretion in the feces. There was no improvement in nitrogen balance in the diets containing cottonseed meal with enzymes.

Ribonucleotide Reduction in Pseudomonas Species: Simultaneous Presence of Active Enzymes from Different Classes

Jordan, Albert; Torrents, Eduard; Sala, Irma; Hellman, Ulf; Gibert, Isidre; Reichard, Peter
Fonte: American Society for Microbiology Publicador: American Society for Microbiology
Tipo: Artigo de Revista Científica
Publicado em /07/1999 Português
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Three separate classes of ribonucleotide reductases exist in nature. They differ widely in protein structure. Class I enzymes are found in aerobic bacteria and eukaryotes; class II enzymes are found in aerobic and anaerobic bacteria; class III enzymes are found in strict and facultative anaerobic bacteria. Usually, but not always, one organism contains only one or two (in facultative anaerobes) classes. Surprisingly, the genomic sequence of Pseudomonas aeruginosa contains sequences for each of the three classes. Here, we show by DNA hybridization that other species of Pseudomonas also contain the genes for three classes. Extracts from P. aeruginosa and P. stutzeri grown aerobically or microaerobically contain active class I and II enzymes, whereas we could not demonstrate class III activity. Unexpectedly, class I activity increased greatly during microaerobic conditions. The enzymes were separated, and the large proteins of the class I enzymes were obtained in close to homogeneous form. The catalytic properties of all enzymes are similar to those of other bacterial reductases. However, the Pseudomonas class I reductases required the continuous presence of oxygen during catalysis, unlike the corresponding Escherichia coli enzyme but similar to the mouse enzyme. In similarity searches...

Tetrameric restriction enzymes: expansion to the GIY-YIG nuclease family

Gasiunas, Giedrius; Sasnauskas, Giedrius; Tamulaitis, Gintautas; Urbanke, Claus; Razaniene, Dalia; Siksnys, Virginijus
Fonte: Oxford University Press Publicador: Oxford University Press
Tipo: Artigo de Revista Científica
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The GIY-YIG nuclease domain was originally identified in homing endonucleases and enzymes involved in DNA repair and recombination. Many of the GIY-YIG family enzymes are functional as monomers. We show here that the Cfr42I restriction endonuclease which belongs to the GIY-YIG family and recognizes the symmetric sequence 5′-CCGC/GG-3′ (‘/’ indicates the cleavage site) is a tetramer in solution. Moreover, biochemical and kinetic studies provided here demonstrate that the Cfr42I tetramer is catalytically active only upon simultaneous binding of two copies of its recognition sequence. In that respect Cfr42I resembles the homotetrameric Type IIF restriction enzymes that belong to the distinct PD-(E/D)XK nuclease superfamily. Unlike the PD-(E/D)XK enzymes, the GIY-YIG nuclease Cfr42I accommodates an extremely wide selection of metal-ion cofactors, including Mg2+, Mn2+, Co2+, Zn2+, Ni2+, Cu2+ and Ca2+. To our knowledge, Cfr42I is the first tetrameric GIY-YIG family enzyme. Similar structural arrangement and phenotypes displayed by restriction enzymes of the PD-(E/D)XK and GIY-YIG nuclease families point to the functional significance of tetramerization.

Functional Diversity of Four Glycoside Hydrolase Family 3 Enzymes from the Rumen Bacterium Prevotella bryantii B14 ▿ †

Dodd, Dylan; Kiyonari, Shinichi; Mackie, Roderick I.; Cann, Isaac K. O.
Fonte: American Society for Microbiology (ASM) Publicador: American Society for Microbiology (ASM)
Tipo: Artigo de Revista Científica
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Prevotella bryantii B14 is a member of the phylum Bacteroidetes and contributes to the degradation of hemicellulose in the rumen. The genome of P. bryantii harbors four genes predicted to encode glycoside hydrolase (GH) family 3 (GH3) enzymes. To evaluate whether these genes encode enzymes with redundant biological functions, each gene was cloned and expressed in Escherichia coli. Biochemical analysis of the recombinant proteins revealed that the enzymes exhibit different substrate specificities. One gene encoded a cellodextrinase (CdxA), and three genes encoded β-xylosidase enzymes (Xyl3A, Xyl3B, and Xyl3C) with different specificities for either para-nitrophenyl (pNP)-linked substrates or substituted xylooligosaccharides. To identify the amino acid residues that contribute to catalysis and substrate specificity within this family of enzymes, the roles of conserved residues (R177, K214, H215, M251, and D286) in Xyl3B were probed by site-directed mutagenesis. Each mutation led to a severely decreased catalytic efficiency without a change in the overall structure of the mutant enzymes. Through amino acid sequence alignments, an amino acid residue (E115) that, when mutated to aspartic acid, resulted in a 14-fold decrease in the kcat/Km for pNP-β-d-xylopyranoside (pNPX) with a concurrent 1.1-fold increase in the kcat/Km for pNP-β-d-glucopyranoside (pNPG) was identified. Amino acid residue E115 may therefore contribute to the discrimination between β-xylosides and β-glucosides. Our results demonstrate that each of the four GH3 enzymes has evolved to perform a specific role in lignopolysaccharide hydrolysis and provide insight into the role of active-site residues in catalysis and substrate specificity for GH3 enzymes.

Ação antimicrobiana de enzimas hidrolíticas produzidas por Trichoderma asperellum e imobilizadas em blendas de polímeros biodegradáveis.; Antimicrobial action of hydrolytic enzymes produced for Trichoderma asperellum and immobilized on biodegradable polymer blends.

SILVA, Barbara Dumas Santos
Fonte: Universidade Federal de Goiás; BR; UFG; Mestrado em Biologia; Ciências Biolóicas Publicador: Universidade Federal de Goiás; BR; UFG; Mestrado em Biologia; Ciências Biolóicas
Tipo: Dissertação Formato: application/pdf
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The hydrolytic activity of enzymes produced by Trichoderma asperellum, immobilized biodegradable films, as growth inhibitor of microorganisms was tested. The inhibitory activity was demonstrated on Aspergillus niger, Penicillium sp. and Sclerotinia sclerotiorum, microorganisms usually related to the attack and/or food contamination at the field or packaged. We used two polymer blends with different compositions, cassava starch and poly-butylene adipate-co-terephthalate (Ecoflex®, BASF Chemical Company) and other composed for polyvinyl alcohol (PVA) and polysaccharide cashew gum (PEJU). T. asperellum was induced to produce enzymes involved in the attack mycoparasite (N-acetylglucosaminidases, β-1,3-glucanases, chitinases and proteases) by the addition of crude chitin in the growth medium. The enzymes produced in major quantity were N-acetylglucosaminidase and chitinase. The pool of enzymes produced in the experiments was then used for immobilization tests. The immobilization process was performed in films by two methods: covalent and ionic bonding. In both methods, the presence of immobilized hydrolytic enzymes resulted in reduced growth of microorganisms, but the covalent immobilization of the results were more expressive. S.sclerotiorum was the microorganism most sensitive...

Marquage fluorescent des protéines pour étudier les enzymes protéolytiques solubles et immobilisées par la cartographie peptidique électrophorétique

Gan, Shao MIng
Fonte: Université de Montréal Publicador: Université de Montréal
Tipo: Thèse ou Mémoire numérique / Electronic Thesis or Dissertation
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La cartographie peptidique est une méthode qui permet entre autre d’identifier les modifications post-traductionnelles des protéines. Elle comprend trois étapes : 1) la protéolyse enzymatique, 2) la séparation par électrophorèse capillaire (CE) ou chromatographie en phase liquide à haute performance (HPLC) des fragments peptidiques et 3) l’identification de ces derniers. Cette dernière étape peut se faire par des méthodes photométriques ou par spectrométrie de masse (MS). Au cours de la dernière décennie, les enzymes protéolytiques immobilisées ont acquis une grande popularité parce qu’elles peuvent être réutilisées et permettent une digestion rapide des protéines due à un rapport élevé d’enzyme/substrat. Pour étudier les nouvelles techniques d’immobilisation qui ont été développées dans le laboratoire du Professeur Waldron, la cartographie peptidique par CE est souvent utilisée pour déterminer le nombre total de peptides détectés et leurs abondances. La CE nous permet d’avoir des séparations très efficaces et lorsque couplée à la fluorescence induite par laser (LIF), elle donne des limites de détection qui sont 1000 fois plus basses que celles obtenues avec l’absorbance UV-Vis. Dans la méthode typique...

Biochemical and molecular characterisation of oenologically important enzymes identified in lactic acid bacteria.

Matthews, Angela H.
Fonte: Universidade de Adelaide Publicador: Universidade de Adelaide
Tipo: Tese de Doutorado
Publicado em //2007 Português
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Enzyme concentrates are available for use in commercial wineries to aid in wine processing, or to enhance wine quality. However, pectolytic enzyme remains the sole product routinely used in most wineries. One disadvantage of some of the products currently available commercially is they contain enzymes sourced from microorganisms not usually associated with grape juice or wine, typically fungi such as Aspergillus species. As a result, enzymes are inefficient catalysts under the harsh oenological conditions. In addition, some products contain secondary, and potentially undesirable, contaminant enzyme activities. Clearly there is the potential to develop enzyme preparations specifically for use in grape juice and wine. A potential source of such enzymes are the lactic acid bacteria (LAB), the organisms more commonly associated with the conduct of the malolactic fermentation (MLF) during vinification. In this study, the production of cell-associated enzymes with potential oenological applications by LAB was investigated. A screening of 50 LAB isolates for the production of lipases, esterases, tannases, and polysaccharide-degrading enzymes revealed wine LAB can produce enzymes of oenological importance. In general, activity towards polysaccharide substrates was more frequent among the lactobacilli and pediococci strains. Lipase activity was observed in three lactobacilli...

Marine-derived fungi: diversity of enzymes and biotechnological applications

Bonugli-Santos, Rafaella C.; Santos Vasconcelos, Maria R. dos; Passarini, Michel R. Z.; Vieira, Gabriela A. L.; Lopes, Viviane C. P.; Mainardi, Pedro H.; Santos, Juliana A. dos; Duarte, Lidia de Azevedo; Otero, Igor V. R.; Silva Yoshida, Aline M. da; Feit
Fonte: Frontiers Research Foundation Publicador: Frontiers Research Foundation
Tipo: Artigo de Revista Científica Formato: 1-15
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq); Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES); Processo FAPESP: 2013/19486-0; Processo FAPESP: 2013/08617-7; Processo FAPESP: 2009/18399-1; Processo FAPESP: 2011/18769-3; Processo FAPESP: 2008/06720-7; Processo FAPESP: 2012/12622-3; Processo FAPESP: 2013/12505-0; Processo FAPESP: 2014/12430-2; Processo FAPESP 2013/00286-1; The ocean is considered to be a great reservoir of biodiversity. Microbial communities in marine environments are ecologically relevant as intermediaries of energy, and play an important role in nutrient regeneration cycles as decomposers of dead and decaying organic matter. In this sense, marine-derived fungi can be considered as a source of enzymes of industrial and/or environmental interest. Fungal strains isolated from different substrates, such as invertebrates, decaying wood, seawater, sediments, and mangrove detritus, have been reported to be producers of hydrolytic and/or oxidative enzymes, with alginate lyase, amylase, cellulase, chitinase, glucosidase, inulinase, keratinase, ligninase, lipase, nuclease, phytase, protease, and xylanase being among the enzymes produced by fungi of marine origin. These enzymes present temperature and pH optima ranging from 35 to 70 degrees C...

Discovering novel carbohydrate-active enzymes in the cellulosome of anaerobic bacteria

Fernandes, Vânia Ondina Pedro
Fonte: Universidade de Lisboa. Faculdade de Medicina Veterinária Publicador: Universidade de Lisboa. Faculdade de Medicina Veterinária
Tipo: Tese de Doutorado
Publicado em 29/09/2015 Português
Relevância na Pesquisa
36.345469%
Tese de Doutoramento em Ciências Veterinárias, especialidade em Ciências Biológicas e Biomédicas; Carbohydrate-active enzymes (CAZymes) include a range of enzymes that, in nature, make, break or modify glycosidic bonds. CAZymes act on highly recalcitrant polysaccharides, such as cellulose and hemicellulose, and often exhibit a modular architecture including catalytic domains fused through flexible linker regions to non-catalytic domains such as carbohydrate-binding modules (CBMs). In some anaerobic bacteria these enzymes can associate in high molecular mass multi-enzyme complexes termed cellulosomes. Cellulosomal organisms express a vast repertoire of plant cell wall degrading enzymes and constitute a promising source for the discovery of novel CAZymes. Presently, an exponential accumulation of genomic and metagenomic information is observed while the identification of the biological role of both genes and proteins of unknown function is sorely lacking. In addition, for most of the known CAZymes, structure and/or biochemical characterization is missing. In this study we have developed innovative approaches for the discovery of novel CAZymes in cellulosomal bacteria and provide a detailed biochemical characterization of some of those enzymes. A high-throughput platform was designed for cloning...

Enzymes in the Synthesis of Bioactive Compounds: The Prodigious Decades

García-Junceda, Eduardo; García-García, Juan Francisco; Bastida, Agatha; Fernández-Mayoralas, Alfonso
Fonte: Pergamon Press Publicador: Pergamon Press
Tipo: Artículo Formato: 731379 bytes; application/pdf
Português
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The growing demand for enantiomerically pure pharmaceuticals has impelled research on enzymes as catalysts for asymmetric synthetic transformations. However, the use of enzymes for this purpose was rather limited until the discovery that enzymes can work in organic solvents. Since the advent of the PCR the number of available enzymes has been growing rapidly and the tailor-made biocatalysts are becoming a reality. Thus, it has been possible the use of enzymes for the synthesis of new innovative medicines such as carbohydrates and their incorporation to modern methods for drug development, such as combinatorial chemistry. Finally, the genomic research is allowing the manipulation of whole genomes opening the door to the combinatorial biosynthesis of compounds. In this review, our intention is to highlight the main landmarks that have led to transfer the chemical efficiency shown by the enzymes in the cell to the synthesis of bioactive molecules in the lab during the last 20 years. In this review, our intention is to highlight the main landmarks of the last 20 years that have led to transfer the chemical efficiency shown by the enzymes in the cell to the synthesis of bioactive molecules in the laboratory.; AB was supported by a postdoctoral I3P contract of the European Social Found. This work was supported by the Spanish DGI (Grants BQU2001-1503 and PTR1995-0568-OP).; Peer reviewed