title: Effects of lacquer polysaccharides, glycoproteins and isoenzymes on the activity of free and immobilised laccase from Rhus vernicifera.
abstract: The purified polysaccharides, glycoproteins, and isoenzymes of Rhus laccase, and crude enzymes, from Chinese lacquer (Rhus vernicifera sap) were used to determine their influence on the enzymic activity of Rhus laccase on several substrates (4-phenylenediamine, isoeugenol and coniferyl alcohol). No product identity changes were observed when these components were added singularly or in combination to the enzymic reactions (only relative product yields varied significantly), however, the polysaccharides (GP1 and GP2) and glycoprotein (stellacyanin, St) exhibited negative effects, and the two isoenzymes (L1 and L2) exhibited positive synergistic effects, on the activity of Rhus laccase. With respect to the activity of the crude enzymes, the negative effects of GP1, GP2 and St were greater than the positive effects of L1 and L2, compared with free Rhus laccase on its own (using 4-phenylenediamine as substrate), the estimated inhibitory effect (of GP1, GP2 and St) being by at least a factor of 50 (even with the positive effect of L1 and L2). This contributes to understanding of lacquer storage stability and drying rates. Immobilisation of crude enzymes using a variety of techniques (using natural and modified polysaccharides, and an inorganic support) where evaluated using isoeugenol as substrate. Agar embedding and zirconium chloride chelation methods resulted in the highest substrate conversion levels. The yields and products of isoeugenol catalysis using Vietnamese crude enzymes/purified Rhus laccase and commercial Denilite laccase were also compared and contrasted with their Chinese lacquer sap equivalents.
authors.affiliation: College of Resource and Environmental Science, Wuhan University, Wuhan 430072, Hubei, China.
authors.forename: Yun-Yang
authors.initials: YY
authors.lastname: Wan
authors.forename: Rong
authors.initials: R
authors.lastname: Lu
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Akiyama
authors.forename: Katsuhisa
authors.initials: K
authors.lastname: Okamoto
authors.forename: Takayuki
authors.initials: T
authors.lastname: Honda
authors.forename: Yu-Min
authors.initials: YM
authors.lastname: Du
authors.forename: Takashi
authors.initials: T
authors.lastname: Yoshida
authors.forename: Tetsuo
authors.initials: T
authors.lastname: Miyakoshi
authors.forename: Charles J
authors.initials: CJ
authors.lastname: Knill
authors.forename: John F
authors.initials: JF
authors.lastname: Kennedy
mesh_terms: D000362:Agar / Q000737:chemistry; D002712:Chlorides / Q000737:chemistry; D004791:Enzyme Inhibitors / Q000737:chemistry*; D006023:Glycoproteins / Q000737:chemistry*; D007527:Isoenzymes / Q000737:chemistry; D042845:Laccase / Q000737:chemistry*; D008667:Metalloproteins / Q000737:chemistry*; D010940:Plant Proteins / Q000737:chemistry*; D011134:Polysaccharides / Q000737:chemistry*; D013379:Substrate Specificity; D012251:Toxicodendron / Q000201:enzymology*; D015040:Zirconium / Q000737:chemistry
chemical_list: D002712:Chlorides; D004791:Enzyme Inhibitors; D006023:Glycoproteins; D007527:Isoenzymes; D008667:Metalloproteins; D010940:Plant Proteins; D011134:Polysaccharides; C003343:stellacyanin protein, plant; D000362:Agar; D015040:Zirconium; D042845:Laccase; C429984:zirconium chloride