Data/hora: 20/06/2024 02:04:07

Biblioteca(s): | Embrapa Mandioca e Fruticultura.
Data corrente: | 10/04/1995
Data da última atualização: | 10/04/1995
Autoria: | OBA, K.; IWATSUKI, N.; URITANI, I.; ALVAREZ, A. M.; GARCIA, V. V.
Título: | Polyphenol oxidase in banana fruit and buds.
Ano de publicação: | 1994
Fonte/Imprenta: | Tokyo, Japan: Japan Scientific Societies Press, 1994.
Páginas: | p.35-46
ISBN: | 4-7622-7755-X
Idioma: | Inglês
Notas: | In: URITANI, I.; GARCIA, V. V.; MENDOZA, E. M. Postharvest Biochemistry of plant food-materials in the tropics.
Conteúdo: | PPO is primarily responsible for the enzymic browning that occurs in banana fruits and buds. This enzyme was extracted from banana buds in the presence of Triton X-100, isoascorbate, and Polyclar AT. Two isozymes, I and II, were separated and partially purified by chromotagraphy on Butyl Toyopearl 650 and DEAE-cellulose. They exhibited different mobilities in PAGE and showed optimum pHs of 6.8 and 5.5, respectively. Both isozymes showed apparent Km values of 0.5 mM for the best substrate, dopamine, with substrate inhibitions at higher concentrations. Isozymes I and II were inhibited competitively by NaCl with Ki values of 140 mM and 40 mM, respectively. Both have a high heat stablitity similar to banana pulp PPO, with respectively 88 and 95% of their initial activity retained after l-hr incubation at 70 grauC.
Palavras-Chave: | Enzimas; Polyphenol.
Thesagro: | Oxidação.
Categoria do assunto: | --
Registro original: | Embrapa Mandioca e Fruticultura (CNPMF)
Exemplares: | CNPMF - (13501-1) - ADD - PL - -- - 581.192 - U76p - 1994000158 - DIS