Characterization of flavonoid 7-O-glucosyltransferase from Arabidopsis thaliana.
Most flavonoids found in plants exist as glycosides, and glycosylation status has a wide range of effects on flavonoid solubility, stability, and bioavailability. Glycosylation of flavonoids is mediated by Family 1 glycosyltransferases (UGTs), which use UDP-sugars, such as UDP-glucose, as the glycosyl donor. AtGT-2, a UGT from Arabidopsis thaliana, was cloned and expressed in Escherichia coli as a gluthatione S-transferase fusion protein. Several compounds, including flavonoids, were tested as potential substrates. HPLC analysis of the reaction products indicated that AtGT-2 transfers a glucose molecule into several different kinds of flavonoids, eriodictyol being the most effective substrate, followed by luteolin, kaempferol, and quercetin. Based on comparison of HPLC retention times with authentic flavonoid 7-O-glucosides and nuclear magnetic resonance spectroscopy, the glycosylation position in the reacted flavonoids was determined to be the C-7 hydroxyl group. These results indicate that AtGT-2 encodes a flavonoid 7-O-glucosyltransferase.
Kim
Jeong Ho
JH
Bio/Molecular Informatics Center, Division of Bioscience and Biotechnology, Konkuk University, Seoul, Korea.
Kim
Bong Gyu
BG
Park
Younghee
Y
Ko
Jae Hyung
JH
Lim
Chae Eun
CE
Lim
Jun
J
Lim
Yoongho
Y
Ahn
Joong-Hoon
JH
D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics; D003001:Cloning, Molecular; D017124:Conserved Sequence; D005419:Flavonoids / Q000737:chemistry / Q000378:metabolism; D015870:Gene Expression; D005964:Glucosyltransferases / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D008969:Molecular Sequence Data; D011994:Recombinant Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D016415:Sequence Alignment; D013379:Substrate Specificity
D005419:Flavonoids; D011994:Recombinant Proteins; D005964:Glucosyltransferases; C083090:flavone 7-O-beta-glucosyltransferase