Дисертації з теми "Enzymatic modifications"
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Guedes, Sofia de Morais Correia Pereira. "Study of oxidation and non-enzymatic glycosylation posttranslational modifications using a proteomic approach." Doctoral thesis, Uniiversidade de Aveiro, 2011. http://hdl.handle.net/10773/7034.
Повний текст джерелаA glicosilação não-enzimática e o stress oxidativo representam dois processos importantes visto desempenharem um papel importante no que respeita às complicações de vários processos patofisiológicos. No presente, a associação entre a glicosilação não-enzimática e a oxidação de proteínas é reconhecida como sendo um dos principais responsáveis pela acumulação de proteínas não-funcionais que, por sua vez, promove uma contínua sensibilização para um aumento do stress oxidativo ao nível celular. Embora esteja disponível bastante informação no que respeita aos dois processos e suas consequências ao nível estrutural e funcional, permanecem questões por esclarecer acerca do que se desenvolve ao nível molecular. Com o objectivo de contribuir para uma melhor compreensão da relação entre a glicosilação não-enzimática e a oxidação, proteínas modelo (albumina, insulina e histonas H2B e H1) foram submetidas a sistemas in vitro de glicosilação não-enzimática e oxidação em condições controladas e durante um período de tempo específico. A identificação dos locais de glicosilação e oxidação foi realizada através de uma abordagem proteómica, na qual após digestão enzimática se procedeu à análise por cromatografia líquida acoplada a espectrometria de massa tandem (MALDI-TOF/TOF). Esta abordagem permitiu a obtenção de elevadas taxas de cobertura das sequências proteicas, permitindo a identificação dos locais preferenciais de glicosilação e oxidação nas diferentes proteínas estudadas. Como esperado, os resíduos de lisina foram os preferencialmente glicosilados. No que respeita à oxidação, além das modificações envolvendo hidroxilações e adições de oxigénio, foram identificadas deamidações, carbamilações e conversões oxidativas específicas de vários aminoácidos. No geral, os resíduos mais afectados pela oxidação foram os resíduos de cisteína, metionina, triptofano, tirosina, prolina, lisina e fenilalanina. Ao longo do período de tempo estudado, os resultados indicaram que a oxidação teve início em zonas expostas da proteína e/ou localizadas na vizinhança de resíduos de cisteína e metionina, ao invés de exibir um comportamente aleatório, ocorrendo de uma forma nãolinear por sua vez dependente da estabilidade conformacional da proteína. O estudo ao longo do tempo mostrou igualmente que, no caso das proteínas préglicosiladas, a oxidação das mesmas ocorreu de forma mais rápida e acentuada, sugerindo que as alterações estruturais induzidas pela glicosilação promovem um estado pro-oxidativo. No caso das proteínas pré-glicosiladas e oxidadas, foi identificado um maior número de modificações oxidativas assim como de resíduos modificados na vizinhança de resíduos glicosilados. Com esta abordagem é realizada uma importante contribuição na investigação das consequências do dano ‘glico-oxidativo’ em proteínas ao nível molecular através da combinação da espectrometria de massa e da bioinformática.
Glycation and oxidative stress are two important processes known to play a key role in complications of many pathophysiological processes. It is nowadays acknowledged the association between glycation and oxidation events as a major responsible for the accumulation of non-functional damaged proteins that in turn promote continuous sensitization to further oxidative stress at the cellular level. Despite the large amount of information concerning both events and their consequences at structural and functional levels, questions remain to answer on what happens at the protein molecular level. With the aim of contributing to better understand the interrelationship between glycation and oxidation, model proteins (BSA, insulin and histones H2B and H1) were submitted to in vitro systems of glycation and oxidation under controlled conditions and through a specific period of time. Identification of glycation and oxidation sites was performed through a proteomics approach. Protein samples were enzimatically digested and further analyzed by nano-liquid chromatography coupled to MALDI-TOF/TOF mass spectrometry. This approach allowed obtaining high protein coverage rates, enabling the identification of the most susceptible sites of glycation and oxidation in the different studied proteins. As expected, lysine residues were preferentially glycated and with respect to oxidation, besides protein hydroxyl derivatives and oxygen additions, modifications such as deamidations, carbamylations and specific amino acid oxidative conversions were detected. In general, the main affected amino acids by oxidative damage were cysteine, methionine, tryptophan, tyrosine, proline, lysine and phenylalanine. The time-course study of the oxidative damage indicated the oxidative attack, rather than occurring randomly, initiates at surface-exposed regions and/or near cysteine and methionine residues and occurs in a non-linear way depending on the conformational stability of the protein. Time-course analysis also showed a more pronounced and earlier occurrence of the oxidative damage in the case of preglycated proteins, suggesting that structural changes caused by glycation induce a pro-oxidant state. This increased oxidative damage included not only a greater number of oxidative modifications, but also of oxidized residues, occurring in the vicinity of the glycated residues. Through this kind of approach, an important contribution is made in the investigation of the consequences of protein ‘glycoxidative’ damage at a molecular level through the profit combination of mass spectrometry and bioinformatics.
Baron, Kim L. "Enzymatic and chemical modifications of erythrocyte surface antigens to identify Plasmodium falciparum merozoite binding sites." Diss., University of Pretoria, 2014. http://hdl.handle.net/2263/46043.
Повний текст джерелаDissertation (MSc)--University of Pretoria, 2014.
tm2015
Pharmacology
MSc
Unrestricted
Simiand, Cécile. "Modifications régio- et stéréosélectives du saccharose." Grenoble 1, 1993. http://www.theses.fr/1993GRE10180.
Повний текст джерелаKutacova, Pavla. "Enzymatic modification of kenaf pulp." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ33973.pdf.
Повний текст джерелаMansfield, Shawn Denton. "Enzymatic modification of Douglas-fir pulp." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/NQ27197.pdf.
Повний текст джерелаDalponte, Luca. "Chemo-enzymatic modification of cyclic peptides." Thesis, University of Aberdeen, 2018. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=239393.
Повний текст джерела簫乃志 and Nai-chi Siu. "Enzymatic modification of oat globulin by microbial transglutaminase." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2001. http://hub.hku.hk/bib/B31225147.
Повний текст джерелаSiu, Nai-chi. "Enzymatic modification of oat globulin by microbial transglutaminase." Hong Kong : University of Hong Kong, 2001. http://sunzi.lib.hku.hk/hkuto/record.jsp?B23234507.
Повний текст джерелаKriek, Marco. "Enzymatic synthesis of complex carbohydrates : approaches to the enzymatic synthesis and chemical modification of oligosaccharides." Thesis, University of Reading, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.342146.
Повний текст джерелаChandra, Richard P. "Chemo-enzymatic modification of high-kappa kraft pulps with laccase." Diss., Available online, Georgia Institute of Technology, 2005, 2003. http://etd.gatech.edu/theses/available/ipstetd-1011/.
Повний текст джерелаWashington, Benny Jr. "Enzymatic modification of synthetic mRNA's and their interaction with proteins." DigitalCommons@Robert W. Woodruff Library, Atlanta University Center, 1985. http://digitalcommons.auctr.edu/dissertations/1244.
Повний текст джерелаXiong, Chen. "Enzymatic modification of DNA and RNA 3'-termini for click ligation." Thesis, University of Southampton, 2014. https://eprints.soton.ac.uk/367127/.
Повний текст джерелаCanela, Xandri Anna. "Chemical and enzymatic valorization of polyols from biomass." Doctoral thesis, Universitat de Lleida, 2016. http://hdl.handle.net/10803/386443.
Повний текст джерелаEn las últimas décadas han aumentado los problemas derivados de la sobreproducción y acumulación de residuos de la industria agroalimentaria, así como los problemas medioambientales y la disminución de fuentes de materias primas. Incrementando así el interés en reutilizarlos, revalorizándolos produciendo productos de interés, acercándonos cada vez más al concepto de residuo cero. Uno de los mayores subproductos de la industria es el conocido con el término de biomasa. En este trabajo, nos hemos centrado en investigar la revalorización de una pequeña parte de los polioles presentes en la biomasa, entre ellos algunos carbohidratos y el glicerol.
In the last decades, problems related with overproduction and industry waste accumulation have increased, causing environmental problems and depletion of raw material sources. Because of that, there has been an increasing interest in the reuse of wastes to prepare valuable products, getting closer to the zero waste concept. Biomass is one of the major agroindustrial by-products. In this work, we were focused on adding-value to a small portion of the polyols present in biomass, including some carbohydrates and glycerol.
Goswami, Luna. "Enzymatic modification of wood cell walls and its influence on material properties and function /." Berlin, 2009. http://opac.nebis.ch/cgi-bin/showAbstract.pl?sys=000256289.
Повний текст джерелаDurá, de Miguel Ángela. "EFFECT OF ENZYMATIC TREATMENTS ON CARBOHYDRATE MATRICES TOWARDS HEALTHY GLUTEN FREE FOODS APPLICATION." Doctoral thesis, Universitat Politècnica de València, 2017. http://hdl.handle.net/10251/79509.
Повний текст джерелаEl almidón es la principal fuente de reserva de energía en las plantas, está ampliamente presente en diversas aplicaciones alimentarias y no alimentarias, y constituye uno de los hidratos de carbono más abundantes en la dieta humana. Además del uso frecuente y clásico del almidón nativo como materia prima en la producción de alimentos, los almidones modificados han experimentado gran expansión en el desarrollo de numerosos productos debido a su carácter versátil. Las modificaciones enzimáticas se llevan a cabo para realzar la funcionalidad del almidón con objeto de soslayar las restricciones tecnológicas y mejorar la calidad del producto final. En concreto, el almidón de maíz ampliamente producido y consumido, es apropiado como ingrediente principal en la producción de alimentos libres de gluten. Esta Tesis aborda el estudio del efecto individual de tres diferentes enzimas, alfa-amylasa fúngica, amiloglucosidasa y ciclodextrina glucosiltransferasa, sobre la temperatura de sub-gelatinización del almidón de maíz. Se realizaron diferentes análisis para ampliar el conocimiento de los cambios estructurales y funcionales asociados a la acción de la enzima. Así mismo, se seleccionó el almidón de maíz modificado con ciclodextrina glucosiltransferasa para investigar la respuesta glicémica en ratones. El índice glicémico se relacionó con la ausencia/presencia de productos de hidrólisis liberados por la acción catalítica de la enzima y las propiedades de gelatinización. Los almidones de maíz enzimáticamente modificados presentaron alteraciones funcionales en los gránulos de almidón, lo que les confiere características de interés para diversos usos alimentarios.
El midó és la principal font de reserva d'energia en les plantes, està àmpliament present en diverses aplicacions alimentàries i no alimentàries, i constitueix un dels hidrats de carboni més abundants en la dieta humana. A més de l'ús freqüent i clàssic del midó natiu com a matèria primera en la producció d'aliments, els midons modificats han experimentat gran expansió en el desenvolupament de nombrosos productes a causa del seu caràcter versàtil. Les modificacions enzimàtiques es duen a terme per a realçar la funcionalitat del midó a fi d'esbiaixar les restriccions tecnològiques i millorar la qualitat del producte final. En concret, el midó de dacsa àmpliament produït i consumit, és apropiat com a ingredient principal en la producció d'aliments lliures de gluten. Aquesta Tesi aborda l'estudi de l'efecte individual de tres diferents enzims, alfa-amylasa fúngica, amiloglucosidasa i ciclodextrina glucosiltransferasa, sobre la temperatura de sub-gelatinizació del midó de dacsa. Es van realitzar diferents anàlisi per a ampliar el coneixement dels canvis estructurals i funcionals associats a l'acció de l'enzim. Així mateix, es va seleccionar el midó de dacsa modificat amb ciclodextrina glucosiltransferasa per a investigar la resposta glicémica en ratolins. L'índex glicémic es va relacionar amb l'absència/presencia de productes d'hidròlisis alliberats per l'acció catalítica de l'enzim i les propietats de gelatinización. Els midons de dacsa enzimàticament modificats van presentar alteracions funcionals en els grànuls de midó, la qual cosa els confereix característiques d'interès per a diversos usos alimentaris.
Durá De Miguel, Á. (2017). EFFECT OF ENZYMATIC TREATMENTS ON CARBOHYDRATE MATRICES TOWARDS HEALTHY GLUTEN FREE FOODS APPLICATION [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/79509
TESIS
Gratzer, Paul F. "The effect of chemical modification on the enzymatic degradation of acellular matrix (ACM) processed biomaterials." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0019/NQ45752.pdf.
Повний текст джерелаScholten, Matthew John. "Enzymatic and chemical modification of fatty acid methyl esters: enzymatic catalysis of methyl linoleate using soybean lipoxygenase and chemical catalysis of methyl oleate Using Hypobromination." Thesis, University of Iowa, 2010. https://ir.uiowa.edu/etd/735.
Повний текст джерелаMoreira, Ana Sofia Pereira. "Study of modifications induced by thermal and oxidative treatment in oligo and polysaccharides of coffee by mass spectrometry." Doctoral thesis, Universidade de Aveiro, 2016. http://hdl.handle.net/10773/17074.
Повний текст джерелаOs polissacarídeos são os componentes maioritários dos grãos de café verde e torrado e da bebida de café. Os mais abundantes são as galactomananas, seguindo-se as arabinogalactanas. Durante o processo de torra, as galactomananas e arabinogalactanas sofrem modificações estruturais, as quais estão longe de estar completamente elucidadas devido à sua diversidade e à complexidade estrutural dos compostos formados. Durante o processo de torra, as galactomananas e arabinogalactanas reagem com proteínas, ácidos clorogénicos e sacarose, originando compostos castanhos de alto peso molecular contendo nitrogénio, designados de melanoidinas. As melanoidinas do café apresentam diversas atividades biológicas e efeitos benéficos para a saúde. No entanto, a sua estrutura exata e os mecanismos envolvidos na sua formação permanecem desconhecidos, bem como a relação estrutura-atividade biológica. A utilização de sistemas modelo e a análise por espectrometria de massa permitem obter uma visão global e, simultaneamente, detalhada das modificações estruturais nos polissacarídeos do café promovidas pela torra, contribuindo para a elucidação das estruturas e mecanismos de formação das melanoidinas. Com base nesta tese, oligossacarídeos estruturalmente relacionados com a cadeia principal das galactomananas, (β1→4)-Dmanotriose (Man3), e as cadeias laterais das arabinogalactanas, (α1→5)-Larabinotriose (Ara3), isoladamente ou em misturas com ácido 5-Ocafeoilquínico (5-CQA), o ácido clorogénico mais abundante nos grãos de café verde, e péptidos compostos por tirosina e leucina, usados como modelos das proteínas, foram sujeitos a tratamento térmico a seco, mimetizando o processo de torra. A oxidação induzida por radicais hidroxilo (HO•) foi também estudada, uma vez que estes radicais parecem estar envolvidos na modificação dos polissacarídeos durante a torra. A identificação das modificações estruturais induzidas por tratamento térmico e oxidativo dos compostos modelo foi feita por estratégias analíticas baseadas principalmente em espectrometria de massa, mas também em cromatografia líquida. A cromatografia de gás foi usada na análise de açúcares neutros e ligações glicosídicas. Para validar as conclusões obtidas com os compostos modelo, foram também analisadas amostras de polissacarídeos do café obtidas a partir de resíduo de café e café instantâneo. Os resultados obtidos a partir dos oligossacarídeos modelo quando submetidos a tratamento térmico (seco), assim como à oxidação induzida por HO• (em solução), indicam a ocorrência de despolimerização, o que está de acordo com estudos anteriores que reportam a despolimerização das galactomananas e arabinogalactanas do café durante a torra. Foram ainda identificados outros compostos resultantes da quebra do anel de açúcares formados durante o tratamento térmico e oxidativo da Ara3. Por outro lado, o tratamento térmico a seco dos oligossacarídeos modelo (individualmente ou quando misturados) promoveu a formação de oligossacarídeos com um maior grau de polimerização, e também polissacarídeos com novos tipos de ligações glicosídicas, evidenciando a ocorrência de polimerização através reações de transglicosilação não enzimática induzidas por tratamento térmico a seco. As reações de transglicosilação induzidas por tratamento térmico a seco podem ocorrer entre resíduos de açúcares provenientes da mesma origem, mas também de origens diferentes com formação de estruturas híbridas, contendo arabinose e manose como observado nos casos dos compostos modelo usados. Os resultados obtidos a partir de amostras do resíduo de café e de café instantâneo sugerem a presença de polissacarídeos híbridos nestas amostras de café processado, corroborando a ocorrência de transglicosilação durante o processo de torra. Além disso, o estudo de misturas contendo diferentes proporções de cada oligossacarídeo modelo, mimetizando regiões do grão de café com composição distinta em polissacarídeos, sujeitos a diferentes períodos de tratamento térmico, permitiu inferir que diferentes estruturas híbridas e não híbridas podem ser formadas a partir das arabinogalactanas e galactomananas, dependendo da sua distribuição nas paredes celulares do grão e das condições de torra. Estes resultados podem explicar a heterogeneidade de estruturas de melanoidinas formadas durante a torra do café. Os resultados obtidos a partir de misturas modelo contendo um oligossacarídeo (Ara3 ou Man3) e 5-CQA sujeitas a tratamento térmico a seco, assim como de amostras provenientes do resíduo de café, mostraram a formação de compostos híbridos compostos por moléculas de CQA ligadas covalentemente a um número variável de resíduos de açúcar. Além disso, os resultados obtidos a partir da mistura contendo Man3 e 5-CQA mostraram que o CQA atua como catalisador das reações de transglicosilação. Por outro lado, nas misturas modelo contendo um péptido, mesmo contendo também 5-CQA e sujeitas ao mesmo tratamento, observou-se uma diminuição na extensão das reações transglicosilação. Este resultado pode explicar a baixa extensão das reações de transglicosilação não enzimáticas durante a torra nas regiões do grão de café mais ricas em proteínas, apesar dos polissacarídeos serem os componentes maioritários dos grãos de café. A diminuição das reações de transglicosilação na presença de péptidos/proteínas pode dever-se ao facto de os resíduos de açúcares redutores reagirem preferencialmente com os grupos amina de péptidos/proteínas por reação de Maillard, diminuindo o número de resíduos de açúcares redutores disponíveis para as reações de transglicosilação. Além dos compostos já descritos, uma diversidade de outros compostos foram formados a partir dos sistemas modelo, nomeadamente derivados de desidratação formados durante o tratamento térmico a seco. Em conclusão, a tipificação das modificações estruturais promovidas pela torra nos polissacarídeos do café abre o caminho para a compreensão dos mecanismos de formação das melanoidinas e da relação estrutura-atividade destes compostos.
Polysaccharides are the major components of green and roasted coffee beans, and coffee brew. The most abundant ones are galactomannans, followed by arabinogalactans. During the roasting process, galactomannans and arabinogalactans undergo structural modifications that are far to be completely elucidated due to their diversity and complexity of the compounds formed. During the roasting process, galactomannans and arabinogalactans react with proteins, chlorogenic acids, and sucrose, originating high molecular weight brown compounds containing nitrogen, known as melanoidins. Several biological activities and beneficial health effects have been attributed to coffee melanoidins. However, their exact structures and the mechanisms involved in their formation remain unknown, as well as the structure-biological activity relationship. The use of model systems and mass spectrometry analysis allow to obtain an overall view and, simultaneously, detailed, of the structural modifications in coffee polysaccharides promoted by roasting, contributing to the elucidation of the structures and formation mechanisms of melanoidins. Based on this thesis, oligosaccharides structurally related to the backbone of galactomannans, (β1→4)-D-mannotriose, and the side chains of arabinogalactans, (α1→5)-Larabinotriose, alone or in mixtures with 5-O-caffeoylquinic acid, the most abundant chlorogenic acid in green coffee beans, and dipeptides composed by tyrosine and leucine, used as models of proteins, were submitted to dry thermal treatments, mimicking the coffee roasting process. The oxidation induced by hydroxyl radicals (HO•) was also studied, since these radicals seem to be involved in the modification of the polysaccharides during roasting. The identification of the structural modifications induced by thermal and oxidative treatment of the model compounds was performed mostly by mass spectrometry-based analytical strategies, but also using liquid chromatography. Gas chromatography was used in the analysis of neutral sugars and glycosidic linkages. To validate the conclusions achieved with the model compounds, coffee polysaccharide samples obtained from spent coffee grounds and instant coffee were also analysed. The results obtained from the model oligosaccharides when submitted to thermal treatment (dry) or oxidation induced by HO• (in solution) indicate the occurrence of depolymerization, which is in line with previous studies reporting the depolymerization of coffee galactomannans and arabinogalactans during roasting. Compounds resulting from sugar ring cleavage were also formed during thermal treatment and oxidative treatment of Ara3. On the other hand, the dry thermal treatment of the model oligosaccharides (alone or when mixed) promoted the formation of oligosaccharides with a higher degree of polymerization, and also polysaccharides with new type of glycosidic linkages, evidencing the occurrence of polymerization via non-enzymatic transglycosylation reactions induced by dry thermal treatment. The transglycosylation reactions induced by dry thermal treatment can occur between sugar residues from the same origin, but also of different origins, with formation of hybrid structures, containing arabinose and mannose in the case of the model compounds used. The results obtained from spent coffee grounds and instant coffee samples suggest the presence of hybrid polysaccharides in these processed coffee samples, corroborating the occurrence of transglycosylation during the roasting process. Furthermore, the study of mixtures containing different proportions of each model oligosaccharide, mimicking coffee bean regions with distinct polysaccharide composition, subjected to different periods of thermal treatment, allowed to infer that different hybrid and non-hybrid structures may be formed from arabinogalactans and galactomannans, depending on their distribution in the bean cell walls and on roasting conditions. These results may explain the heterogeneity of melanoidins structures formed during coffee roasting. The results obtained from model mixtures containing an oligosaccharide (Ara3 or Man3) and 5-CQA and subjected to dry thermal treatment, as well as samples derived from spent coffee grounds, showed the formation of hybrid compounds composed by CQA molecules covalently linked to a variable number of sugar residues. Moreover, the results obtained from the mixture containing Man3 and 5-CQA showed that CQA acts as catalyst of transglycosylation reactions. On the other hand, in the model mixtures containing a peptide, even if containing 5-CQA and subjected to the same treatment, it was observed a decrease in the extent of transglycosylation reactions. This outcome can explain the low extent of non-enzymatic transglycosylation reactions during roasting in coffee bean regions enriched in proteins, although polysaccharides are the major components of the coffee beans. The decrease of transglycosylation reactions in the presence of peptides/proteins can be related with the preferential reactivity of reducing residues with the amino groups of peptides/proteins by Maillard reaction, decreasing the number of reducing residues available to be directly involved in the transglycosylation reactions. In addition to the compounds already described, a diversity of other compounds were formed from model systems, namely dehydrated derivatives formed during dry thermal treatment. In conclusion, the identification of the structural modifications in coffee polysaccharides promoted by roasting pave the way to the understanding of the mechanisms of formation of melanoidins and structure-activity relationship of these compounds.
Sweeney, Deacon John. "A Computational Tool for Biomolecular Structure Analysis Based On Chemical and Enzymatic Modification of Native Proteins." Wright State University / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=wright1316440232.
Повний текст джерелаPersson, Per. "Strategies for cellulose fiber modification." Doctoral thesis, KTH, Fibre and Polymer Technology, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3730.
Повний текст джерелаThis thesis describes strategies for and examples ofcellulose fiber modification.The ability of an engineered biocatalyst, acellulose-binding module fused to theCandida antarcticalipase B, to catalyze ring-openingpolymerization of e-caprolactone in close proximity tocellulose fiber surfaces was explored. The water content in thesystem was found to regulate the polymer molecular weight,whereas the temperature primarily influenced the reaction rate.The hydrophobicity of the cellulose sample increased as aresult of the presence of surface-deposited polyester.
A two-step enzymatic method was also investigated. Here,Candida antarctica lipase B catalyzed the acylation ofxyloglucan oligosaccharides.The modified carbohydrates werethen incorporated into longer xyloglucan molecules through theaction of a xyloglucan endotransglycosylase. The modifiedxyloglucan chains were finally deposited on a cellulosesubstrate.
The action ofCandida antarcticalipase B was further investigated inthe copolymerization of e-caprolactone and D,L-lactide.Copolymerizations with different e-caprolactone-to-D,L-lactideratios were carried out. Initially, the polymerization wasslowed by the presence of D,L-lactide. During this stage,D,L-lactide was consumed more rapidly than ε-caprolactoneand the incorporation occurred dimer-wise with regard to thelactic acid units.
Morphological studies on wood fibers were conducted using asol-gel mineralization method. The replicas produced werestudied, without additional sample preparation, by electronmicroscopy and nitrogen adsorption. Information concerning thestructure and accessibility of the porous fiber wall wasobtained. Studies of never-dried kraft pulp casts revealedmicro-cavities and cellulose fibrils with mean widths of 4.7(±2) and 3.6 (±1) nm, respectively.
Finally, cationic catalysis by simple carboxylic acids wasstudied. L-Lactic acid was shown to catalyze the ring-openingpolymerization of ε-caprolactone in bulk at 120 °C.The reaction was initiated with methylß-D-glucopyranoside, sucrose or raffinose, which resultedin carbohydrate-functionalized polyesters. The regioselectivityof the acylation was well in agreement with the correspondinglipase-catalyzed reaction. The polymerization was alsoinitiated with a hexahydroxy-functional compound, whichresulted in a dendrimer-like star polymer. The L-lactic acidwas readily recycled, which made consecutive reactions usingthe same catalyst possible.
Keywords:Candida antarcticalipase B, cationic catalysis,cellulose-binding module, dendrimer, enzymatic polymerization,fiber modification, silica-cast replica, sol-gelmineralization, organocatalysis, xyloglucanendotransglycosylase
King, Elizabeth Caroline. "Studies on the modification and enzymatic hydrolysis of poly(#gamma#-D-glutamic acid) from Bacillus licheniformis 9945A." Thesis, University of Southampton, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.266658.
Повний текст джерелаElangwe, Emilia N. "Site Directed Mutagenesis, Expression and Enzymatic Studies of the 60 kDa Human HIV-TAT 1 Interactive Protein, TIP60." Digital Archive @ GSU, 2009. http://digitalarchive.gsu.edu/chemistry_theses/21.
Повний текст джерелаNaolou, Toufik [Verfasser], Jörg [Akademischer Betreuer] Kreßler, and Carmen [Akademischer Betreuer] Scholz. "Enzymatic synthesis of functional polyesters and their modification by grafting reactions / Toufik Naolou. Betreuer: Jörg Kreßler ; Carmen Scholz." Halle, Saale : Universitäts- und Landesbibliothek Sachsen-Anhalt, 2014. http://d-nb.info/1052221297/34.
Повний текст джерелаRousseau, Dérick. "Modification of the physical and compositional properties of butter fat-canola oil blends by chemical and enzymatic interesterification." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/nq24424.pdf.
Повний текст джерелаNemoto-Smith, Emi H. "Synthesis of cobalamin analogues using enzymatic and chemical modification methods, and subsequent identification of cobalamin localisation in a variety of organisms." Thesis, University of Kent, 2017. https://kar.kent.ac.uk/61694/.
Повний текст джерелаCarr, Jason A. "The Utilization of Enzymes in the Synthesis and Modification of Natural and NonNatural Compounds: A Chemo-Enzymatic Approach to Enantiomerically Pure Compounds." Scholar Commons, 2004. https://scholarcommons.usf.edu/etd/983.
Повний текст джерелаCarr, Jason A. "The utilization of enzymes in the synthesis and modification of natural and non-natural compounds a chemo-enzymatic approach to enantiomerically pure compounds /." [Tampa, Fla.] : University of South Florida, 2004. http://purl.fcla.edu/fcla/etd/SFE0000420.
Повний текст джерелаClaisse, Nathalie. "Préparation et modification d'oligosaccharides de cellulose par chimie douce bio-inspirée." Phd thesis, Université de Grenoble, 2012. http://tel.archives-ouvertes.fr/tel-00849149.
Повний текст джерелаBOISSET, CLAIRE. "Modification de materiaux cellulosiques par des enzymes cellulolytiques." Université Joseph Fourier (Grenoble), 1996. http://www.theses.fr/1996GRE10225.
Повний текст джерелаLe, Costaouëc Tinaïg. "Élucidation structurale et modifications d'un exopolysaccharide bactérien d'origine hydrothermale." Brest, 2010. http://www.theses.fr/2010BRES2062.
Повний текст джерелаBacteria are known to produce exopolysaccharides (EPS) with a great diversity of structures and are an important source of polysaccharides with new properties. Among those, the EPS HYD 657 or deepsane is produced by a marine bacteria: Alteromonas macleodii subsp. Fijiensis biovar deepsane, collected around deep-sea hydrothermal vents. This high molecular weigh EPS (>106 g/mol) is already used in cosmetics but its structure remained unknown so that the first aim of this study consists in elucidating its repeating unit. The data show a very complex branched repeating unit of 16-18 sugars with 7 different types of monosaccharides (neutral and acidic) and 3 types of substituents (sulphate, lactyl and pyruvyl groups). Analyses of native and oligomeric fragments from Smith degradation allow us to identify two oligosaccharides of this repeating unit and the position of two substituents. In order to enlarge the application field of this EPS, two depolymerization processes were studied. After comparison of the first one know process (free-radical depolymerization) and development of a second one (ball-milling), two low molecular weigh EPS were prepared and sulphate groups were added: they show interesting properties in modulating a way of the immune system. To enlarge depolymerization tools of this EPS, the research of enzymatical activities s developed in the third part. Protein extracts were generated by cultivating the strain producing J IN L 657 under EPS-producing conditions. One of those extracts was shown to be active to depolymerize this EPS
Döring, Clemens [Verfasser], Thomas [Akademischer Betreuer] Becker, Eckhard [Gutachter] Flöter, and Thomas [Gutachter] Becker. "Interrelation between arabinoxylan and protein during network formation over enzymatic modification in rye based food systems / Clemens Döring ; Gutachter: Eckhard Flöter, Thomas Becker ; Betreuer: Thomas Becker." München : Universitätsbibliothek der TU München, 2020. http://d-nb.info/1217783725/34.
Повний текст джерелаBillig, Susan. "Abbau von Polyethylenterephthalat mit PET-Hydrolasen aus Thermobifida fusca KW3." Doctoral thesis, Universitätsbibliothek Chemnitz, 2012. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-85714.
Повний текст джерелаAlvarez, Albarran Alejandra. "Modular Surface Functionalization of Polyisobutylene-based Biomaterials." University of Akron / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=akron1405173637.
Повний текст джерелаChooi, Kok Phin. "Synthetic phosphorylation of kinases for functional studies in vitro." Thesis, University of Oxford, 2014. https://ora.ox.ac.uk/objects/uuid:2adc517a-2876-4a0b-8ead-e9bf164ebc6f.
Повний текст джерелаVuillemin, Marie. "Auto-assemblage de polysaccharides fonctionnalisés : une étude thermodynamique." Electronic Thesis or Diss., Université de Lorraine, 2019. http://www.theses.fr/2019LORR0177.
Повний текст джерелаPolymers in solution can self-assemble to form different types of complexes (coacervates, aggregates, etc.). These objects, in addition to being part of the cellular organization, can be repurposed to encapsulate molecules of interest. However, before being able to use them as such, the understanding of the self-assembly mechanisms is essential to be able to control them and thus form targeted objects. This thesis work focuses on the self-assembly between gum Arabic and chitosan. The interactions involved in associative phase separation are mainly based on electrostatic interactions. Initially, the formation of this complex was analyzed from a thermodynamic point of view by isothermal calorimetric titration, depending on the physicochemical parameters, in particular the pH, the temperature and the molar ratio. It was thus demonstrated that an increase in temperature or pH favored enthalpy and disfavored entropy and that it was possible to form coacervates under all studied conditions by controlling the pH/temperature combination. To change the number and nature of the interactions between polysaccharides, they were modified by enzymatic pathway. A process developed at the laboratory, based on the use of a laccase to oxidize ferulic acid, has been implemented. First, the modification of gum Arabic was demonstrated, in particular with the support of spectroscopic tools (IR-FT, NMR). In addition, the structure of the numerous oxidation products has been studied (NMR, LCMS). The products obtained are mainly ferulic acid dimers and a complete structure has been elucidated. The products grafted on the gum are of phenolic nature so their grafting has an impact on its techno-functional properties (water solubility, thermal and rheological behavior, surface tension, antioxidant properties, etc.). Finally, the grafting of phenolic compounds modified the polysaccharides hydrophobia and charges, so they were mixed in order to determine the impact of these new groups on the interactions involved in the self-assemblies and the nature of the complexes formed. Under given conditions and depending on the polysaccharides used, it is possible to form coacervates, aggregates or even a mixture of both. The formation of these objects was correlated with a study of the thermodynamic parameters involved. These results paves the way for understanding and controlling complexation between polysaccharides that, in the longer term, will lead to applications in the field of encapsulation
Schuh, Susanne. "Enzymatische Oligomerisierung von Lebensmittelproteinen unter Hochdruck: Reaktionsorte und funktionelle Konsequenzen." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2013. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-113345.
Повний текст джерелаWirth, Petra. "Enzymes en solvants organiques." Grenoble 2 : ANRT, 1988. http://catalogue.bnf.fr/ark:/12148/cb37619244x.
Повний текст джерелаHammam, Kahina. "Nouveau concept de resensibilisation à la chimiothérapie en activant la nucléoside kinase dCK par le masitinib, un inhibiteur de protéines tyrosine kinases." Thesis, Aix-Marseille, 2014. http://www.theses.fr/2014AIXM5047.
Повний текст джерелаResistance to chemotherapy is considered as one of the major blockers of its efficacy. Recently, our team demonstrated that masitinib, a new tyrosine kinases inhibitor, possesse a resensitization activity of cell lines resistant to chemotherapy when associated with chemodrugs.The aim of this work is to determine signaling pathways, modulated by masitinib action, that could explain the resensitization to chemotherapy and improvement of anti-tumoral activity.In the first part of this work, we identified the nucleoside kinase dCK (deoxycytidine kinase), a chemotherapy activating protein, as a new target of masitinib. In summary, this first part of the work allowed us to describe a new and never described concept: masitinib, a small molecule belonging to tyrosine kinases group, can also play a role as nucleoside kinase activator.We were able to demonstrate through the second part of the work that the combined treatment of the epidrug decitabine and masitinib can be more effective than decitabine treatment for the re-expression of some genes non or weakly induced by decitabine when used alone.In conclusion, These data allowed us to introduce an interaction between a tyrosine kinases inhibitor and a nucleoside kinase, as an enzymatic activation new concept. This could be used as a base for the design of new small chemical molecules specific for dCK or other nucleoside kinases essential for the activation of chemodrugs. This concept will obviously help to imagine and evaluate more potential therapeutic combinations of chemodrugs and small chemical molecules to overcome the resistance to chemotherapy dependent on nucleoside kinases
Nadhom, Hama. "Protein Microparticles for Printable Bioelectronics." Thesis, Linköpings universitet, Biosensorer och bioelektronik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-119637.
Повний текст джерелаAldiab, Dima [Verfasser]. "LC-ESI-MS-MS analysis of non-enzymatic posttranslational protein modifications / vorgelegt von Dima Aldiab." 2011. http://d-nb.info/1013086279/34.
Повний текст джерелаMansfield, Shawn Denton. "Enzymatic modification of Douglas-fir pulp." Thesis, 1997. http://hdl.handle.net/2429/8563.
Повний текст джерелаHunter, Janice Lee. "Enzymatic modification of pectin for improved functional properties." 2002. http://purl.galileo.usg.edu/uga%5Fetd/hunter%5Fjanice%5Fl%5F200212%5Fms.
Повний текст джерелаDirected by Louise Wicker. Includes articles submitted to Journal of agricultural and food chemitry, and Food hydrocolloids. Includes bibliographical references.
Mani, Michele A. "Enzymatic modification of butterfat in supercritical carbon dioxide." 1992. http://catalog.hathitrust.org/api/volumes/oclc/31733776.html.
Повний текст джерелаTypescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 113-124).
Wallace, Jeff Thomas. "An enzymatic fiber modification method for enhancing tissue properties." 2006. http://www.lib.ncsu.edu/theses/available/etd-03172006-152042/unrestricted/etd.pdf.
Повний текст джерелаPinterits, Alexandra. "Improvement of canola protein gelation properties through enzymatic modification." Thesis, 2006. http://hdl.handle.net/1993/276.
Повний текст джерелаOctober 2006
Eissa, Ahmed Sherif. "Enzymatic modification of whey protein gels at low pH." 2005. http://www.lib.ncsu.edu/theses/available/etd-01182005-000222/unrestricted/etd.pdf.
Повний текст джерелаLI, JIA-ZHAN, and 李嘉展. "Enzymatic modification on fish proteins to improve the gelation by transglutaminase." Thesis, 1991. http://ndltd.ncl.edu.tw/handle/18530045071964202802.
Повний текст джерелаWang, Lijun. "Discovery and Characterization of Microbial Esterases for Fiber Modification." Thesis, 2009. http://hdl.handle.net/1807/25709.
Повний текст джерелаStrey, Elsie Grethe. "Enzymatic modification of woody cell walls for improved stability of pulp fibres." Diss., 2010. http://hdl.handle.net/2263/28516.
Повний текст джерелаDissertation (PhD)--University of Pretoria, 2010.
Microbiology and Plant Pathology
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Ferreira, Lino da Silva. "Enzymatic modification of carbohydrates with vinyl monomers. Application to the preparation of hydrogels." Doctoral thesis, 2003. http://hdl.handle.net/10316/1676.
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