title: Purification and characterization of UDP-glucose : curcumin glucoside 1,6-glucosyltransferase from Catharanthus roseus cell suspension cultures.
abstract: Catharanthus roseus cell suspension cultures converted exogenously added curcumin to a series of curcumin glucosides that possessed drastically enhanced water solubility. A cDNA clone encoding a glucosyltransferase responsible for glucosylation of curcumin to form curcumin 4'-O-glucoside was previously isolated, and in the present study a novel sugar-sugar glycosyltransferase, UDP-glucose:curcumin glucoside glucosyltransferase (UCGGT), was purified approximately 900-fold to apparent homogeneity from cultured cells of C. roseus. The purified enzyme (0.2% activity yield) catalyzed 1,6-glucosylation of curcumin 4'-O-glucoside to yield curcumin 4'-O-gentiobioside. The molecular weight and isoelectric point were estimated to be about 50 kDa and 5.2, respectively. The enzyme showed a pH optimum between 7.5 and 7.8. Both flavonoid 3-O- and 7-O-glucosides were also preferred acceptor substrates of the enzyme, whereas little activity was shown toward simple phenolic glucosides such as arbutin and glucovanillin, cyanogenic glucoside (prunasin) or flavonoid galactoside. These results suggest that UCGGT may also function in the biosynthesis of flavonoid glycosides in planta.
authors.affiliation: Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya, 467-8603 Japan.
authors.forename: Yukie
authors.initials: Y
authors.lastname: Oguchi
authors.forename: Sayaka
authors.initials: S
authors.lastname: Masada
authors.forename: Toshiya
authors.initials: T
authors.lastname: Kondo
authors.forename: Kazuyoshi
authors.initials: K
authors.lastname: Terasaka
authors.forename: Hajime
authors.initials: H
authors.lastname: Mizukami
mesh_terms: D030008:Catharanthus / Q000166:cytology / Q000201:enzymology* / Q000378:metabolism; D002478:Cells, Cultured; D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D002852:Chromatography, Ion Exchange; D002853:Chromatography, Liquid; D003474:Curcumin / Q000737:chemistry / Q000378:metabolism; D005964:Glucosyltransferases / Q000302:isolation & purification / Q000378:metabolism*; D015394:Molecular Structure; D010940:Plant Proteins / Q000302:isolation & purification / Q000378:metabolism*; D014532:Uridine Diphosphate Glucose / Q000378:metabolism*
chemical_list: D010940:Plant Proteins; D005964:Glucosyltransferases; D003474:Curcumin; D014532:Uridine Diphosphate Glucose