Data/hora: 01/06/2024 02:16:45

Provedor de dados: 	52	
País: 	Brazil	
Título: 	Ionically Bound Peroxidase from Peach Fruit	
Autores: 	Neves,Valdir Augusto.	
Data: 	2002-03-01	
Ano: 	2002	
Palavras-chave: 	Peach peroxidases; Ripening; Purification; Kinetics; Heat stability.	
Resumo: 	Soluble, ionically bound peroxidase (POD) and polyphenoloxidase (PPO) were extracted from the pulp of peach fruit during ripening at 20°C. Ionically bound form was purified 6.1-fold by DEAE-cellulose and Sephadex G-100 chromatography. The purified enzyme showed only one peak of activity on Sephadex G-100 and PAGE revealed that the enzyme was purified by the procedures adopted. The purified enzyme showed a molecular weight of 29000 Da, maximum activity at pH 5.0 and at 40ºC. The calculated apparent activation energy (Ea) for the reaction was10.04 kcal/mol. The enzyme was heat-labile in the temperature range of 60 to 75ºC with a fast inactivation at 75ºC. Measurement of residual activity showed a stabilizing effect of sucrose at various temperature/sugar concentrations (0, 10, 20 %, w/w), with an activation energy (Ea) for inactivation increasing with sucrose concentration from 0 to 20% (w/w). The Km and Vmax values were 9.35 and 15.38 mM for 0-dianisidine and H2O2, respectively. The bound enzyme was inhibited competitively by ferulic, caffeic and protocatechuic acids with different values of Ki,. L-cysteine, p-coumaric and indolacetic acid and Fe++ also inhibited the enzyme but at a lower grade. N-ethylmaleimide and p-CMB were not effective to inhibit the enzyme demonstrating the non-essentiality of SH groups.	
Tipo: 	Info:eu-repo/semantics/article	
Idioma: 	Inglês	
Identificador: 	http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132002000100002	
Editor: 	Instituto de Tecnologia do Paraná - Tecpar	
Relação: 	10.1590/S1516-89132002000100002	
Formato: 	text/html	
Fonte: 	Brazilian Archives of Biology and Technology  v.45 n.1 2002	
Fonte: 	info:eu-repo/semantics/openAccess