Abstract
Calycosin-7-O-β-D-glucoside (Cy7G) is one of the principal components of Radix astragali. This isoflavonoid glucoside is regarded as an indicator to assess the quality of R. astragali and exhibits diverse pharmacological activities. In this study, uridine diphosphate-dependent glucosyltransferase (UGT) UGT88E18 was isolated from Glycine max and expressed in Escherichia coli. Recombinant UGT88E18 could selectively and effectively glucosylate the C7 hydroxyl group of calycosin to synthesize Cy7G. A one-pot reaction by coupling UGT88E18 to sucrose synthase (SuSy) from G. max was developed. The UGT88E18–SuSy cascade reaction could recycle the costly uridine diphosphate glucose (UDPG) from cheap sucrose and catalytic amounts of uridine diphosphate (UDP). The important factors for UGT88E18–SuSy cascade reaction, including UGT88E18/SuSy ratios, different temperatures, and pH values, different concentrations of dimethyl sulfoxide (DMSO), UDP, sucrose, and calycosin, were optimized. We produced 10.5 g L−1 Cy7G in the optimal reaction conditions by the stepwise addition of calycosin. The molar conversion of calycosin was 97.5%, with a space–time yield of 747 mg L−1 h−1 and a UDPG recycle of 78 times. The present study provides a new avenue for the efficient and cost-effective semisynthesis of Cy7G and other valuable isoflavonoid glucosides by UGT–SuSy cascade reaction.
Highlights
Flavonoids are a group of structurally diverse, plant-derived polyphenols widely present in fruits, vegetables, and beverages [1,2]
N-terminal His6 -tagged UGT88E18 was heterologously expressed in Escherichia coli BL21 (DE3), UGT88E18 from G. max was specific for isoflavones, including genistein and daidzein [23]
N-terminal His6-tagged UGT88E18 was heterologously expressed in Escherichia coli BL21 (DE3), and band at around 72.2 kDa that corresponded to the calculated molecular weight of recombinant purified by one-step nickel chelate affinity chromatography
Summary
Flavonoids are a group of structurally diverse, plant-derived polyphenols widely present in fruits, vegetables, and beverages [1,2]. Extensive studiesthat indicate thatsynthase sucrose (SuSy) synthase a versatile biocatalyst that can synthesize costly uridine diphosphate glucose (UDPG). A considerable number of UGTs involved in the glucosylation of flavonoids have been isolated products and functionally characterized from involved plants [21]. The regioselective and effective and functionally characterized from plants [21] These UGTs typically tolerate a broad range of glucosylation calycosin was achieved using. The regioselective and a UGT88E18–SuSy cascade reaction was developed to synthesize using cheap sucrose as effective glucosylation of calycosin was achieved using UGT88E18 isolated from Glycine max.the. Cascade reaction was developed to synthesize Cy7G using cheap sucrose addition, UGT88E18–SuSy as the expedient glucosyl donor In expedientaglucosyl donor. cascade reaction was developed to synthesize Cy7G using cheap sucrose addition, UGT88E18–SuSy as the expedient glucosyl donor
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
