Please use this identifier to cite or link to this item: http://hdl.handle.net/2440/13048
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Type: Journal article
Title: Cloning and characterization of vitis vinifera UDP-glucose: Flavonoid 3-O-glucosyltransferase, a homologue of the enzyme encoded by the maize bronze-1 locus that may primarily serve to glucosylate anthocyanidins in vivo
Author: Ford, C.
Boss, P.
Hoj, P.
Citation: Journal of Biological Chemistry, 1998; 273(15):9224-9233
Publisher: American Society for Biochemistry and Molecular Biology
Issue Date: 1998
ISSN: 1083-351X
1083-351X
Statement of
Responsibility: 
Christopher M. Ford, Paul K. Boss, and Peter Bordier Høj
Abstract: We report here the cloning and optimized expression at 16 °C and the characterization of a Vitis vinifera UDP-glucose:flavonoid 3-O-glucosyltransferase, an enzyme responsible for a late step in grapevine anthocyanin biosynthesis. The properties of this and other UDP-glucose:flavonoid 3-O-glucosyltransferases, homologues of the product encoded by the maize Bronze-1locus, are a matter of conjecture. The availability of a purified recombinant enzyme allowed for the unambiguous determination of the characteristics of a flavonoid 3-O-glucosyltransferase. Kinetic analyses showed that k cat for glucosylation of cyanidin, an anthocyanidin substrate, is 48 times higher than for glucosylation of the flavonol quercetin, whereasK m values are similar for both substrates. Activity toward other classes of substrates is absent. Cu2+ ions strongly inhibit the action of this and other glucosyltransferases; however, we suggest that this phenomenon in large part is due to Cu2+-mediated substrate degradation rather than inhibition of the enzyme. Additional lines of complementary biochemical data also indicated that in the case of V. vinifera, the principal, if not only, role of UDP-glucose:flavonoid 3-O-glucosyltransferases is to glucosylate anthocyanidins in red fruit during ripening. Other glucosyltransferases with a much higher relative activity toward quercetin are suggested to glucosylate flavonols in a distinct spatial and temporal pattern. It should be considered whether gene products homologous to Bronze-1 in some cases more accurately should be referred to as UDP-glucose:anthocyanidin 3-O-glucosyltransferases.
Keywords: Zea mays; Rosales; Copper; Anthocyanins; Glucosyltransferases; Recombinant Proteins; DNA Primers; Cloning, Molecular; Polymerase Chain Reaction; Sequence Alignment; Amino Acid Sequence; Sequence Homology, Amino Acid; Substrate Specificity; Glycosylation; Kinetics; Genes, Plant; Molecular Weight; Molecular Sequence Data
Rights: © 1998 by The American Society for Biochemistry and Molecular Biology, Inc.
RMID: 0030003811
DOI: 10.1074/jbc.273.15.9224
Appears in Collections:Wine Science publications

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