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영어

Kaempferol is a natural flavonol. It reduces the risk of various cancers and also has skin-lightening effect. Due to these efficacies, the possible application in food, medicine and cosmetics industry are increasing. But these flavonols has limited application due to water solubility and stability. Considering these demerits, synthesized Astragalin (kaempferol-3-O-β-D-glucopyranoside) from kaempferol using uridine 5′-diphosphate (UDP)-3-O-glycosyltransferase. (UDP)-3-O-glycosyltransferase (UGT78K1) was expressed in E. coli BL21 (DE3) which utilize the bacterial indigenous UDP-glucose as sugar donor to catalyze glycosylation reaction. During biotransformation reaction kaempferol was exogenously fed and the product was isolated as Astragalin. To use UDP-glucose efficiently, previously constructed recombinant mono-cistronic vector (piBR181) was used which contained UDP-glucose biosynthetic pathway genes (pgm2: phosphoglucomutase and galU: glucose 1-phosphate uridylyltransferase) along with D-glucose facilitator proteins (glf: glucose facilitator diffusion protein), glucokinase (glk: glucokinase) and glycosyltransferases (UGT78K1) in mono-cistronic fashion. Luria-Bertani (LB) media was used for biotransformation reaction while cell induction was done using Lactose. Highest product conversion was achieved and were confirmed by HPLC-PDA analyses comparing with previous result.