Produção e caracterização da atividade de tirosinase no extrato bruto de Pycnoporus sanguineus CCT-4518
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Data
2009-07-15
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Universidade Federal de Goiás
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
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Citação
DUARTE, Livia Teixeira. Production and characterization of tyrosinase activity in Pycnoporus sanguineus
CCT-4518 crude extract. 2009. 74 f. Dissertação (Mestrado em Ciências da Saúde - Farmácia) - Universidade Federal de Goiás, Goiânia, 2009.