title: Pectin methylesterase from kiwi and kaki fruits: purification, characterization, and role of pH in the enzyme regulation and interaction with the kiwi proteinaceous inhibitor.
abstract: Pectin methylesterase was purified from kiwi (Actinidia chinensis) and kaki fruit (Diospyros kaki). The pH values of the fruit homogenates were 3.5 and 6.2, respectively. The kiwi enzyme is localized in the cell wall and has a neutral-alkaline pI, whereas the kaki enzyme is localized in the soluble fraction and has a neutral-acidic pI. The molecular weights of the kiwi and kaki enzymes were 50 and 37 kDa, respectively. The two enzymes showed a similar salt and pH dependence of activity, and a different pH dependence of the inhibition by the kiwi proteinaceous inhibitor.
authors.affiliation: Institute of Protein Biochemistry, CNR, Via Marconi 12, I-80125 Naples, Italy. ma.ciardiello@ibp.cnr.it
authors.forename: M Antonietta
authors.initials: MA
authors.lastname: Ciardiello
authors.forename: Maurizio
authors.initials: M
authors.lastname: Tamburrini
authors.forename: Lisa
authors.initials: L
authors.lastname: Tuppo
authors.forename: Vito
authors.initials: V
authors.lastname: Carratore
authors.forename: Alfonso
authors.initials: A
authors.lastname: Giovane
authors.forename: Benedetta
authors.initials: B
authors.lastname: Mattei
authors.forename: Laura
authors.initials: L
authors.lastname: Camardella
mesh_terms: D029042:Actinidia / Q000201:enzymology*; D000595:Amino Acid Sequence; D002265:Carboxylic Ester Hydrolases / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism*; D002473:Cell Wall / Q000201:enzymology; D029788:Diospyros / Q000201:enzymology*; D004791:Enzyme Inhibitors / Q000378:metabolism*; D005638:Fruit / Q000201:enzymology*; D006863:Hydrogen-Ion Concentration; D008969:Molecular Sequence Data; D008970:Molecular Weight
chemical_list: D004791:Enzyme Inhibitors; D002265:Carboxylic Ester Hydrolases; C022323:pectinesterase