title: Characterization of polyphenol oxidase from Cape gooseberry (Physalis peruviana L.) fruit.
abstract: Cape gooseberry (Physalis peruviana) is an exotic fruit highly valued, however it is a very rich source of polyphenol oxidase (PPO). In this study, Cape gooseberry PPO was isolated and biochemically characterized. The enzyme was extracted and purified using acetone and aqueous two-phase systems. The data indicated that PPO had the highest substrate affinity for chlorogenic acid, 4-methylcatechol and catechol. Chlorogenic acid was the most suitable substrate (Km=0.56±0.07 mM and Vmax=53.15±2.03 UPPO mL(-1) min(-1)). The optimal pH values were 5.5 for catechol and 4-methylcatechol and 5.0 for chlorogenic acid. Optimal temperatures were 40°C for catechol, 25°C for 4-methylcatechol and 20°C for chlorogenic acid. In inhibition tests, the most potent inhibitor was found to be ascorbic acid followed by L-cysteine and quercetin. This study shows possible treatments that can be implemented during the processing of Cape gooseberry fruits to prevent browning.
authors.affiliation: Grupo de Investigación en Sustancias Bioactivas, Facultad de Ciencias Farmacéuticas y Alimentarias, Universidad de Antioquia UdeA, Calle 70 No. 52-21, Medellín, Colombia.
authors.forename: Karent
authors.initials: K
authors.lastname: Bravo
authors.affiliation: Grupo de Investigación en Sustancias Bioactivas, Facultad de Ciencias Farmacéuticas y Alimentarias, Universidad de Antioquia UdeA, Calle 70 No. 52-21, Medellín, Colombia. Electronic address: edison.osorio@udea.edu.co.
authors.forename: Edison
authors.initials: E
authors.lastname: Osorio
mesh_terms: D001205:Ascorbic Acid / Q000032:analysis; D004156:Catechol Oxidase / Q000037:antagonists & inhibitors / Q000302:isolation & purification*; D002396:Catechols / Q000737:chemistry; D002726:Chlorogenic Acid / Q000737:chemistry; D003545:Cysteine / Q000032:analysis; D004795:Enzyme Stability; D005638:Fruit / Q000201:enzymology*; D008970:Molecular Weight; D032321:Physalis / Q000201:enzymology*; D013379:Substrate Specificity; D013696:Temperature
chemical_list: D002396:Catechols; C018599:4-methylcatechol; D002726:Chlorogenic Acid; D004156:Catechol Oxidase; D003545:Cysteine; C034221:catechol; D001205:Ascorbic Acid
keywords: Cape gooseberry; Characterization; Inhibition; Polyphenol oxidase; Purification