title: Separation of an isoenzyme of polyphenol oxidase from Duranta plumieri by expanded bed chromatography.
abstract: Aqueous extracts of seeds of Duranta plumieri were found to be rich in polyphenol oxidase activity. The anion-exchange chromatography of the crude extract on Streamline DEAE resolved the activity into three fractions. The major fraction (77% of the total activity) was further purified by treating it with concanavalin A-agarose in the batch mode. The enzyme preparation eluting with alpha-methylmannoside showed a single band on SDS-PAGE. The minimum molecular weight corresponded to 14,000 Da. The K(m) and V(max) of this isoenzyme were found to be 7.1 mM and 73.5 U ml(-1) min(-1) respectively. The k(cat) of this isoenzyme was calculated to be 8235 s(-1). The isoenzyme also showed the phenomenon of latency and the activity could be enhanced by 196% on heating it at 55 degrees C for 30 min.
authors.affiliation: Chemistry Department, Indian Institute of Technology, Delhi, Hauz Khas, New Delhi, 110 016, India.
authors.forename: Ipsita
authors.initials: I
authors.lastname: Roy
authors.forename: Shweta
authors.initials: S
authors.lastname: Sharma
authors.forename: Munishwar Nath
authors.initials: MN
authors.lastname: Gupta
mesh_terms: D004156:Catechol Oxidase / Q000302:isolation & purification*; D002847:Chromatography, Agarose; D002852:Chromatography, Ion Exchange / Q000379:methods*; D003208:Concanavalin A; D007527:Isoenzymes / Q000302:isolation & purification*; D007700:Kinetics; D037121:Plant Lectins; D012639:Seeds / Q000737:chemistry; D012685:Sepharose
chemical_list: D007527:Isoenzymes; D037121:Plant Lectins; D003208:Concanavalin A; D012685:Sepharose; D004156:Catechol Oxidase