Detalhes bibliográficos
| Ano de defesa: |
2009 |
| Autor(a) principal: |
DUARTE, Livia Teixeira
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| Orientador(a): |
BARA, Maria Teresa Freitas
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| Banca de defesa: |
Não Informado pela instituição |
| Tipo de documento: |
Dissertação
|
| Tipo de acesso: |
Acesso aberto |
| Idioma: |
por |
| Instituição de defesa: |
Universidade Federal de Goiás
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| Programa de Pós-Graduação: |
Mestrado em Ciências Farmacêuticas
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| Departamento: |
Ciências da Saúde - Farmácia
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| País: |
BR
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| Palavras-chave em Português: |
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| Palavras-chave em Inglês: |
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| Área do conhecimento CNPq: |
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| Link de acesso: |
http://repositorio.bc.ufg.br/tede/handle/tde/2127
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Resumo: |
Tyrosinase (E.C.1.14.18.1) is an enzyme of industrial interest that catalyses the ohydroxylation of monophenols (monophenolase activity) and the oxidation of o-diphenols to reactive o-quinones (diphenolase activity), both reactions using molecular oxygen. Pycnoporus sanguineus (L. ex Fries) Murril, is a white rot fungi capable of producing tyrosinase and widely distributed in nature. It is found in regions of mild climate and in tropical forest. The production and characterization of tyrosinase from P. sanguineus were investigated. The selection of inductors, determination of the luminosity influence, biomass and culture media in the production of tyrosinase and the effect of inhibitors on enzyme activity were determined. The fungus produced intracellular tyrosinase and the higher activity was observed using 0.15% L-tyrosine as inducer, in the presence of light, with inoculum of 10 mycelium discs, medium malt extract broth 2%, incubation at 30°C, and constant agitation of 150 rpm, during 2 days. 6 mmol.L-1 salicylhydroxamic acid (SHAM) and 6 mmol.L-1 phenylthiourea (PTU) inhibited 100% of the tyrosinase activity. 0.1 mmol.L-1 sodium azide inhibited 4.15% of tyrosinase activity, while no inhibition was observed after addition of 0.1 mmol.L-1 of phenylmethanesulfonyl fluoride (PMSF). Using L-dopa as substrate, the intracellular crude extract presented optimum pH of 6,6, optimum temperature of 45°C, low stability at 50°C, maintaining about 50% of the activity after 15 min of incubation. The tyrosinase production was confirmed by non-denaturing polyacrylamide gel electrophoresis, using commercial fungal tyrosinase as positive control |
