Active bionanoconjugates of laccase and gold nanoparticles: kinetic and structural studies

Detalhes bibliográficos
Autor(a) principal: Couto, Cláudia Alexandra Maia do
Data de Publicação: 2012
Tipo de documento: Dissertação
Idioma: eng
Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
Texto Completo: http://hdl.handle.net/10362/8145
Resumo: Thesis for the master degree in Structural and Functional Biochemistry
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spelling Active bionanoconjugates of laccase and gold nanoparticles: kinetic and structural studiesGold nanoparticlesLaccaseBionanoconjugatesImmobilizationThesis for the master degree in Structural and Functional BiochemistryThe work presented here had the objective of using gold nanoparticles (AuNPs) functionalized with mercaptoundecanoic acid (MUA), or the peptide CALNN, to develop bionanoconjugates (BNCs) with the enzyme Rhus vernicifera (Rv) laccase. Laccases are multi copper oxidases able to catalyze the oxidation of a variety of phenolic compounds with the reduction of molecular oxygen to water, and conjugating this enzyme with AuNPs could potentially contribute to enhance its catalytic activity. Spectroscopic, electrophoretic, kinetic, and computer modelling studies were carried out in order to characterize the enzyme structurally and investigate its stability and activity when conjugated with AuNPs. The studies performed revealed that Rv laccase is a monomer with 5.65 ± 0.83 nm in diameter and presents an optimal activity at pH 7.5, when syringaldazine was used as substrate. Laccase was successfully adsorbed to AuNP-CALNN but not to AuNP-MUA. BNCs with laccase and AuNP-CALNN remained active in the experimental conditions tested at pH from 6 – 8.5. Laccase followed a Michaelis-Menten kinetic model using syringaldazine as a substrate, in the pH range 6 – 8.5. Parallel studies with free laccase were conducted to evaluate the influence of AuNP-CALNN on laccase activity. These kinetic studies were performed by following substrate consumption and product formation. The kinetic results with less error were obtained when the reaction of product formation was followed. Therefore, the results for product formation were considered to be more reliable than the results obtained for substrate consumption. The results for product formation revealed that the catalytic efficiency of BNCs was more than 50% higher at pH 7, almost 100% higher at pH 7.5 and 30% higher at pH 8 in comparison with free laccase. At pH 6 there was a decrease of approximately 38% in the catalytic efficiency. The catalytic efficiency was similar in BNCs and free laccase at pH 6.5 and 8.5. In the pH range 6.5 to 8.5, AuNP-CALNN proved beneficial by either maintaining or increasing the catalytic activity of laccase. Using AuNP-CALNN to immobilize laccase might allow decreasing industrial costs, recycling the enzyme and improving the outcome of processes usually achieved with free laccase, such as delignification, wine clarification, textile dye bleaching or waste water detoxification.Faculdade de Ciências e TecnologiaFranco, RicardoRUNCouto, Cláudia Alexandra Maia do2012-11-15T16:09:46Z20122012-01-01T00:00:00Zinfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/masterThesisapplication/pdfhttp://hdl.handle.net/10362/8145enginfo:eu-repo/semantics/openAccessreponame:Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)instname:Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informaçãoinstacron:RCAAP2024-03-11T03:40:37Zoai:run.unl.pt:10362/8145Portal AgregadorONGhttps://www.rcaap.pt/oai/openaireopendoar:71602024-03-20T03:17:58.584961Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) - Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informaçãofalse
dc.title.none.fl_str_mv Active bionanoconjugates of laccase and gold nanoparticles: kinetic and structural studies
title Active bionanoconjugates of laccase and gold nanoparticles: kinetic and structural studies
spellingShingle Active bionanoconjugates of laccase and gold nanoparticles: kinetic and structural studies
Couto, Cláudia Alexandra Maia do
Gold nanoparticles
Laccase
Bionanoconjugates
Immobilization
title_short Active bionanoconjugates of laccase and gold nanoparticles: kinetic and structural studies
title_full Active bionanoconjugates of laccase and gold nanoparticles: kinetic and structural studies
title_fullStr Active bionanoconjugates of laccase and gold nanoparticles: kinetic and structural studies
title_full_unstemmed Active bionanoconjugates of laccase and gold nanoparticles: kinetic and structural studies
title_sort Active bionanoconjugates of laccase and gold nanoparticles: kinetic and structural studies
author Couto, Cláudia Alexandra Maia do
author_facet Couto, Cláudia Alexandra Maia do
author_role author
dc.contributor.none.fl_str_mv Franco, Ricardo
RUN
dc.contributor.author.fl_str_mv Couto, Cláudia Alexandra Maia do
dc.subject.por.fl_str_mv Gold nanoparticles
Laccase
Bionanoconjugates
Immobilization
topic Gold nanoparticles
Laccase
Bionanoconjugates
Immobilization
description Thesis for the master degree in Structural and Functional Biochemistry
publishDate 2012
dc.date.none.fl_str_mv 2012-11-15T16:09:46Z
2012
2012-01-01T00:00:00Z
dc.type.status.fl_str_mv info:eu-repo/semantics/publishedVersion
dc.type.driver.fl_str_mv info:eu-repo/semantics/masterThesis
format masterThesis
status_str publishedVersion
dc.identifier.uri.fl_str_mv http://hdl.handle.net/10362/8145
url http://hdl.handle.net/10362/8145
dc.language.iso.fl_str_mv eng
language eng
dc.rights.driver.fl_str_mv info:eu-repo/semantics/openAccess
eu_rights_str_mv openAccess
dc.format.none.fl_str_mv application/pdf
dc.publisher.none.fl_str_mv Faculdade de Ciências e Tecnologia
publisher.none.fl_str_mv Faculdade de Ciências e Tecnologia
dc.source.none.fl_str_mv reponame:Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
instname:Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação
instacron:RCAAP
instname_str Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação
instacron_str RCAAP
institution RCAAP
reponame_str Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
collection Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
repository.name.fl_str_mv Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) - Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação
repository.mail.fl_str_mv
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