title: Biochemical characterization of the suberization-associated anionic peroxidase of potato.
abstract: The anionic peroxidase associated with the suberization response in potato (Solanum tuberosum L.) tubers during wound healing has been purified and partially characterized at the biochemical level. It is a 45-kD, class III (plant secretory) peroxidase that is localized to suberizing tissues and shows a preference for feruloyl (o-methoxyphenol)-substituted substrates (order of substrate preference: feruloyl > caffeoyl > p-coumaryl approximately syringyl) such as those that accumulate in tubers during wound healing. There was little influence on oxidation by side chain derivatization, although hydroxycinnamates were preferred over the corresponding hydroxycinnamyl alcohols. The substrate specificity pattern is consistent with the natural substrate incorporation into potato wound suberin. In contrast, the cationic peroxidase(s) induced in response to wound healing in potato tubers is present in both suberizing and nonsuberizing tissues and does not discriminate between hydroxycinnamates and hydroxycinnamyl alcohols. A synthetic polymer prepared using E-[8-(13)C]ferulic acid, H(2)O(2), and the purified anionic enzyme contained a significant amount of cross-linking through C-8, albeit with retention of unsaturation.
authors.affiliation: Program in Chemistry, University of Northern British Columbia, 3333 University Way, Prince George, British Columbia, Canada V2N 4Z9. bernards@julian.uwo.ca
authors.forename: M A
authors.initials: MA
authors.lastname: Bernards
authors.forename: W D
authors.initials: WD
authors.lastname: Fleming
authors.forename: D B
authors.initials: DB
authors.lastname: Llewellyn
authors.forename: R
authors.initials: R
authors.lastname: Priefer
authors.forename: X
authors.initials: X
authors.lastname: Yang
authors.forename: A
authors.initials: A
authors.lastname: Sabatino
authors.forename: G L
authors.initials: GL
authors.lastname: Plourde
mesh_terms: D002412:Cations / Q000378:metabolism; D003373:Coumaric Acids / Q000378:metabolism; D004790:Enzyme Induction; D006139:Guaiacol / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D007527:Isoenzymes / Q000737:chemistry / Q000145:classification / Q000302:isolation & purification / Q000378:metabolism; D007700:Kinetics; D008055:Lipids; D008563:Membrane Lipids / Q000378:metabolism*; D008970:Molecular Weight; D010084:Oxidation-Reduction; D010544:Peroxidases / Q000737:chemistry / Q000145:classification / Q000302:isolation & purification / Q000378:metabolism*; D010636:Phenols / Q000378:metabolism; D018517:Plant Roots / Q000201:enzymology / Q000378:metabolism*; D011198:Solanum tuberosum / Q000201:enzymology* / Q000502:physiology; D013379:Substrate Specificity; D013696:Temperature
chemical_list: D002412:Cations; D003373:Coumaric Acids; D007527:Isoenzymes; D008055:Lipids; D008563:Membrane Lipids; D010636:Phenols; D006139:Guaiacol; C065875:suberin; D010544:Peroxidases; C120494:anionic peroxidase