Recombinant Expression and Characterization of an Alkali-tolerant UDP-Glycosyltransferase from Solanum lycopersicum and Its Biosynthesis of Gastrodin

Gastrodin is the main bioactive component of Gastrodia elata, which has many excellent pharmacological activities. In this study, UDP-glycosyltransferase from Solanum lycopersicum (SlyUGT) was overexpressed, purified and characterized, and it can be used for biosynthesis of gastrodin. The SlyUGT maximum enzyme activity was 29.48 mU/ml, and its relative molecular weight was about 78.5 kDa. The SlyUGT was purified 16.1-fold by GST affinity resin with an overall recovery of 53.9% and specific activity of 20.9 mU/mg. The optimal temperature of SlyUGT was 40°C, and it exhibited excellent thermal stability at 35°C and 40°C. Furthermore, the SlyUGT had the highest activity at pH 9.5 and good pH stability at pH 5.5-10.5. The enzyme can tolerate low concentrations of DMSO and UDP. In addition, the values of K_M and V_max were found to be 0.65 mM and 74.60 mU/mg respectively. The SlyUGT could convert pHBA into gastrodin by using UDP-glucose as a sugar donor. Under the optimal biosynthesis conditions, the gastrodin production reached 559.83 mg/l, and the corresponding molar conversion rate reached 97.82%. The results showed that SlyUGT has potential application value in the preparation of gastrodin.