Find in Library

Glycyrrhetic acid 3-<i>O</i>-mono-<i>β</i>-d-glucuronide (GAMG), a rare and innovative compound in licorice, exhibits high-potency sweetness and improved physiological activities. However, low amounts of GAMG from plants cannot meet the demands of growing markets. In this study, an efficient one-pot multienzyme cascade reaction for GAMG biosynthesis was constructed using a coupled catalysis of glycosyltransferase and uridine 5′-diphosphate (UDP) glucuronic acid (GlcA) regeneration system. The <i>Glycyrrhiza uralensis</i> glycosyltransferase UGT73F15 was expressed in <i>Escherichia coli</i> BL21 (DE3). The optimal reaction conditions of UGT73F15 were found to be pH 7.5 and 35 °C. The catalytic efficiency (<i>k</i>_cat/<i>K</i>_m) for glycyrrhetic acid (GA) was 2.14 min⁻¹ mM⁻¹ when using UDP-GlcA as sugar donor. To regenerate costly UDP-GlcA, the one-pot multienzyme cascade reaction including UGT73F15, sucrose synthase, UDP-glucose dehydrogenase, and lactate dehydrogenase was adopted to synthesize GAMG from GA on the basis of the UDP-GlcA regeneration system. By optimizing the cascade reaction conditions, the GAMG production successfully achieved 226.38 mg/L. Our study developed an economical and efficient one-pot multienzyme cascade method for facile synthesis of GAMG and other bioactive glucuronosides.