title: Flavanone-specific 7-O-glucosyltransferase activity in Citrus paradisi seedlings: purification and characterization.
abstract: The isolation and characterization of a flavanone-specific 7-O-glucosyltransferase and its resolution from other glucosyltransferases in Citrus paradisi (grapefruit) seedlings is described. This new enzyme in the subclass 2.4.1 catalyzes the glucosylation of the 7-OH group of naringenin (4',5',7-trihydroxyflavanone) to prunin and has been purified (943-fold) by fractional precipitation with ammonium sulfate and successive chromatography on Sephadex G-100, hydroxyapatite, UDP-glucuronic acid agarose, Mono Q, and Mono P columns. It has a pH optimum of 7.5-8.0, an apparent pI of 4.3, and an apparent Mr of 54,900. This glucosyltransferase has an expressed specificity for the 7-position of the flavanones naringenin (Kmapp 62 microM; Kmapp UDPG 51 microM) and hesperetin (Kmapp 124 microM; Kmapp UDPG 243 microM) and did not accept other flavone or flavonol aglycones. Characteristics of other flavonoid glucosyltransferase activities found in grapefruit seedlings are also described.
authors.affiliation: Department of Biology, University of South Florida, Tampa 33620.
authors.forename: C A
authors.initials: CA
authors.lastname: McIntosh
authors.forename: L
authors.initials: L
authors.lastname: Latchinian
authors.forename: R L
authors.initials: RL
authors.lastname: Mansell
mesh_terms: D000645:Ammonium Sulfate; D002845:Chromatography; D002846:Chromatography, Affinity; D002850:Chromatography, Gel; D002852:Chromatography, Ion Exchange; D017886:Durapatite; D004591:Electrophoresis, Polyacrylamide Gel; D005638:Fruit; D005964:Glucosyltransferases / Q000302:isolation & purification* / Q000378:metabolism; D006882:Hydroxyapatites; D007700:Kinetics; D008970:Molecular Weight; D010944:Plants / Q000201:enzymology*; D013379:Substrate Specificity
chemical_list: D006882:Hydroxyapatites; D017886:Durapatite; D005964:Glucosyltransferases; C065994:flavanone 7-O-beta-glucosyltransferase; D000645:Ammonium Sulfate