title: Oxidation of pentagalloylglucose to the ellagitannin, tellimagrandin II, by a phenol oxidase from Tellima grandiflora leaves.
abstract: A new enzyme has been isolated from leaves of the weed Tellima grandiflora (fringe cups, Saxifragaceae) that catalyzed the O(2)-dependent oxidation of 1,2,3,4,6-penta-O-galloyl-beta-D-glucopyranose to tellimagrandin II, the first intermediate in the (4)C(1)-glucose derived series of ellagitannins. CD-spectra revealed that the 4,6-O-HHDP-residue of the in vitro product had the (S)-stereoconfiguration characteristic of tellimagrandin II from natural sources. The enzyme, for which a M(r) of ca. 60,000 was determined, was purified to apparent homogeneity. It had a pH-optimum at pH 5.0, an isoelectric point at pH 6.3 and was most stable at pH 4.2. Inhibition studies suggested that this new enzyme, for which the systematic name 'pentagalloylglucose: O(2) oxidoreductase' is proposed, belongs to the vast group of laccase-type phenol oxidases (EC 1.10.3.2).
authors.affiliation: Molekulare Botanik, Universität Ulm, D-89069 Ulm, Germany.
authors.forename: Ruth
authors.initials: R
authors.lastname: Niemetz
authors.forename: Georg G
authors.initials: GG
authors.lastname: Gross
mesh_terms: D002851:Chromatography, High Pressure Liquid / Q000379:methods; D004591:Electrophoresis, Polyacrylamide Gel; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005707:Gallic Acid / Q000031:analogs & derivatives* / Q000097:blood* / Q000378:metabolism*; D005960:Glucosides / Q000097:blood*; D006863:Hydrogen-Ion Concentration; D047348:Hydrolyzable Tannins / Q000031:analogs & derivatives* / Q000737:chemistry / Q000378:metabolism*; D008970:Molecular Weight; D014442:Monophenol Monooxygenase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D010084:Oxidation-Reduction; D018515:Plant Leaves / Q000201:enzymology*; D031995:Saxifragaceae / Q000145:classification / Q000201:enzymology*; D013237:Stereoisomerism; D013634:Tannins / Q000096:biosynthesis*
chemical_list: D004791:Enzyme Inhibitors; D005960:Glucosides; D047348:Hydrolyzable Tannins; D013634:Tannins; C013515:ellagitannin; C473299:tellimagrandin II; C435084:pentagalloylglucose; D005707:Gallic Acid; D014442:Monophenol Monooxygenase