Regiospecific methylation of naringenin to ponciretin by soybean O-methyltransferase expressed in Escherichia coli

Kim, Dae Hwan; Kim, Bong-Gyu; Lee, Youngshim; Ryu, Ji Young; Lim, Yoongho; Hur, Hor‐Gil; Ahn, Joong‐Hoon

doi:10.1016/j.jbiotec.2005.04.004

Cited by 82 publications

(60 citation statements)

References 15 publications

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“…It was not surprising that the basil F7OMTs and F49OMTs are related to previously reported F7OMTs and F49OMTs that are also regioselective and non Mg 2+ dependent (Schröder et al, 2004;Willits et al, 2004;Kim et al, 2005Kim et al, , 2006Schmidt et al, 2011). In contrast, our finding that 6-O-methylation is largely engendered by a small family of F49OMT-like, partly bifunctional class II small molecule OMTs in basil trichomes was rather unexpected, since both earlier studies regarding flavonoid (flavonol) 6-OMTs described Mg 2+ -dependent enzymes Ibrahim, 1985a, 1985b;Ibdah et al, 2003).…”

Section: Discussion Functional Differentiation Of Class II Omts Contrsupporting

confidence: 72%

A Set of Regioselective O-Methyltransferases Gives Rise to the Complex Pattern of Methoxylated Flavones in Sweet Basil

2012

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Polymethoxylated flavonoids occur in a number of plant families, including the Lamiaceae. To date, the metabolic pathways giving rise to the diversity of these compounds have not been studied. Analysis of our expressed sequence tag database for four sweet basil (Ocimum basilicum) lines afforded identification of candidate flavonoid O-methyltransferase genes. Recombinant proteins displayed distinct substrate preferences and product specificities that can account for all detected 7-/6-/49-methylated, 8-unsubstituted flavones. Their biochemical specialization revealed only certain metabolic routes to be highly favorable and therefore likely in vivo. Flavonoid O-methyltransferases catalyzing 49-and 6-O-methylations shared high identity (approximately 90%), indicating that subtle sequence changes led to functional differentiation. Structure homology modeling suggested the involvement of several amino acid residues in defining the proteins' stringent regioselectivities. The roles of these individual residues were confirmed by site-directed mutagenesis, revealing two discrete mechanisms as a basis for the switch between 6-and 49-O-methylation of two different substrates. These findings delineate major pathways in a large segment of the flavone metabolic network and provide a foundation for its further elucidation.

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Section: Discussion Functional Differentiation Of Class II Omts Contrsupporting

confidence: 72%

A Set of Regioselective O-Methyltransferases Gives Rise to the Complex Pattern of Methoxylated Flavones in Sweet Basil

2012

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“…The structure of these compounds was depicted by means of 1D and 2D NMR spectroscopy and the comparison of those published data. The identified compounds were: keshonin (2) [12], saturejin (3′-(2,5-dihydroxy-p-cymene) 5,7,4′-trihydroxyflavone) (3) [6], ponciretin (4) [13], 5,6-dihydroxy-3′,4′,7-trimethoxyflavone (5) [14], 5,6-dihydroxy-4′,7-dimethoxyflavone (6) [15], and acacetin (7) [6]. Compounds 2-5 were the first isolated from S. khuzistanica.…”

Section: Present Studymentioning

confidence: 99%

Monoterpene Flavonoid from Aerial Parts of Satureja khuzistanica

Davoodi¹,

Rustaiyan²,

Ebrahimi³

2018

Rec.Nat.Prod.

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Fractionation of methanolic extract of Satureja khuzistanica Jamzad by Sephadex LH-20 and reverse phase chromatography led to the isolation and purification of a new monoterpene flavonoid (1), as well as six previously detected flavonoid derivatives (2-6). The structure assignment has been performed by using 1D, 2D NMR, and high-resolution MS spectrometry. In addition, electronic circular dichroism (ECD) spectroscopy was used to reveal the absolute configuration of 1.

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“…290 Biosynthesis of isosakuranetin has been poorly studied. 307,308 Preliminary evidence of the existence of a " fl avanone synthase, " which converts chalcone glycosides into fl avanone glycosides, was presented in 1956. The enzymatic activity of fl avanone synthase responsible for poncirin chalcone ' s conversion into poncirin was studied using various sources including Citrus , Poncirus , Cosmos , and Dahlia .…”

Section: Homentioning

confidence: 99%