title: Molecular cloning and biochemical characterization of three Concord grape (Vitis labrusca) flavonol 7-O-glucosyltransferases.
abstract: Grapes berries produce and accumulate many reactive secondary metabolites, and encounter a wide range of pathogen- and human-derived xenobiotic compounds. The enzymatic glucosylation of these metabolites changes their reactivity, stability and subcellular location. Two ESTs with more than 90% nucleotide sequence identity to three full-length glucosyltransferases are expressed in several grape tissues. The full-length clones have more than 60% amino acid sequence similarity to previously characterized flavonoid 7-O-glucosyltransferases, catechin O-glucosyltransferases and anthocyanin 5-O-glucosyltransferases. In vitro, these enzymes glucosylate flavonols and the xenobiotic 2,4,5-trichlorophenol (TCP). Kinetic analysis indicates that TCP is the preferred substrate for these enzymes, while expression analysis reveals variable transcription of these genes in grape leaves, flowers and berry tissues. The in vivo role of these Vitis labrusca glucosyltransferases is discussed.
authors.affiliation: Department of Biological Sciences, Brock University, 500 Glenridge Ave, St. Catharines, ON, L2S 3A1, Canada.
authors.forename: Dawn
authors.initials: D
authors.lastname: Hall
authors.forename: Kyung Hee
authors.initials: KH
authors.lastname: Kim
authors.forename: Vincenzo
authors.initials: V
authors.lastname: De Luca
mesh_terms: D000872:Anthocyanins / Q000032:analysis / Q000378:metabolism; D001483:Base Sequence; D002733:Chlorophenols / Q000378:metabolism*; D003001:Cloning, Molecular; D044948:Flavonols / Q000032:analysis / Q000378:metabolism*; D035264:Flowers / Q000737:chemistry / Q000201:enzymology / Q000235:genetics; D005638:Fruit / Q000737:chemistry / Q000201:enzymology / Q000235:genetics; D018506:Gene Expression Regulation, Plant; D018745:Genome, Plant / Q000235:genetics; D005964:Glucosyltransferases / Q000235:genetics / Q000378:metabolism*; D007700:Kinetics; D010802:Phylogeny; D018515:Plant Leaves / Q000737:chemistry / Q000201:enzymology / Q000235:genetics; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D030821:Plants, Genetically Modified; D011993:Recombinant Fusion Proteins; D016415:Sequence Alignment; D013379:Substrate Specificity; D027843:Vitis / Q000737:chemistry / Q000201:enzymology* / Q000235:genetics
chemical_list: D000872:Anthocyanins; D002733:Chlorophenols; D044948:Flavonols; D010940:Plant Proteins; D011993:Recombinant Fusion Proteins; C009534:2,4,5-trichlorophenol; D005964:Glucosyltransferases