title: Activity and process stability of purified green pepper (Capsicum annuum) pectin methylesterase.
abstract: Pectin methylesterase (PME) from green bell peppers (Capsicum annuum) was extracted and purified by affinity chromatography on a CNBr-Sepharose-PMEI column. A single protein peak with pectin methylesterase activity was observed. For the pepper PME, a biochemical characterization in terms of molar mass (MM), isoelectric points (pI), and kinetic parameters for activity and thermostability was performed. The optimum pH for PME activity at 22 degrees C was 7.5, and its optimum temperature at neutral pH was between 52.5 and 55.0 degrees C. The purified pepper PME required the presence of 0.13 M NaCl for optimum activity. Isothermal inactivation of purified pepper PME in 20 mM Tris buffer (pH 7.5) could be described by a fractional conversion model for lower temperatures (55-57 degrees C) and a biphasic model for higher temperatures (58-70 degrees C). The enzyme showed a stable behavior toward high-pressure/temperature treatments.
authors.affiliation: Department of Chemistry, Universidade de Aveiro, Campus Santiago, 3810-193 Aveiro, Portugal.
authors.forename: Sónia Marília
authors.initials: SM
authors.lastname: Castro
authors.forename: Ann
authors.initials: A
authors.lastname: Van Loey
authors.forename: Jorge Alexandre
authors.initials: JA
authors.lastname: Saraiva
authors.forename: Chantal
authors.initials: C
authors.lastname: Smout
authors.forename: Marc
authors.initials: M
authors.lastname: Hendrickx
mesh_terms: D002212:Capsicum / Q000201:enzymology*; D002265:Carboxylic Ester Hydrolases / Q000302:isolation & purification / Q000378:metabolism*; D002846:Chromatography, Affinity; D004795:Enzyme Stability; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D010368:Pectins / Q000494:pharmacology; D012965:Sodium Chloride / Q000494:pharmacology; D013696:Temperature
chemical_list: D012965:Sodium Chloride; D010368:Pectins; D002265:Carboxylic Ester Hydrolases; C022323:pectinesterase