Data/hora: 10/06/2024 00:58:25

Provedor de dados: | 52
País: | Brazil
Título: | Some Biochemical properties of polyphenoloxidase from spearmint (Mentha arvensis)
Autores: | Neves,Valdir Augusto; Picchi,Douglas Gatte; Silva,Maraiza Aparecida da.
Data: | 2009-08-01
Ano: | 2009
Palavras-chave: | Polyphenoloxidase; Mentha arvensis; Characterization; Heat inactivation; Inhibitors.
Resumo: | Polyphenoloxidase (PPO; EC 1.14.18.1) extracted from Mentha arvensis leaves was isolated by (NH4)2SO4 precipitation and extensive dialysis. Its optimum pH and temperature varied with the substrate. The PPO showed activity with various diphenols. Km values were found 0.825, 0.928 and 7.41mM for caffeic acid, 4-methylcatechol and catechol, respectively. On heat-inactivation, half of the activity was lost after 60 and 15 sec at 70 and 75ºC, respectively. Measuring of residual activity showed a stabilizing effect of sucrose at various temperatures with activation energy (Ea) for inactivation increasing with sucrose concentration from 0 to 40% (w/w). Ea values of 78.13; 80.37; 82.79 and 81.00 kJ/Mol were found for 0, 15; 30 and 40% sucrose, respectively. PPO was inhibited by ascorbic, benzoic, cinnamic, ferulic, p-coumaric, protocatechuich acids, sodium metabisulfite, pyrogallol and resorcinol. The Ki values showed that ascorbic acid was the most effective inhibitor. The type inhibition was determined for each inhibitor.
Tipo: | Info:eu-repo/semantics/article
Idioma: | Inglês
Identificador: | http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132009000400025
Editor: | Instituto de Tecnologia do Paraná - Tecpar
Relação: | 10.1590/S1516-89132009000400025
Formato: | text/html
Fonte: | Brazilian Archives of Biology and Technology  v.52 n.4 2009
Fonte: | info:eu-repo/semantics/openAccess