원문정보
초록
영어
The main functions of glycosylation are stabilization, detoxification and solubilization of substrates and products. To produce glycosylated products, Escherichia coli was engineered by overexpression of UDPxylose, UDP-glucoronic acid, TDP-L-rhamnose and TDP-6-deoxy-Dallose biosynthetic gene clusters, and flavonoids were glycosylated by the overexpression of the glycosyltransferase gene from Arabidopsis thaliana. For the glycosylation, these flavonoids (ficetin, quercetin, kaempferol and other one) were exogenously fed to the host in a biotransformation system. The products were isolated, analyzed and confirmed by HPLC, LC/MS, NMR and ESI-MS/MS analyses. Several conditions, substrate concentration, incubation time) were optimized to increase the production level. We successfully isolated approximately 24 mg/L 3-O-rhamnosyl quercetin and 12.9 mg/L 3-O-rhamnosyl kaempferol upon feeding of 0.2 mM of the respective flavonoids and were also able to isolate 3-O-allosyl quercetin. Thus, this study reveals a method that might be useful for the biosynthesis of rhamnosyl and allosyl flavonoids and for the glycosylation of related compounds.