Characterization of UDP-glucose 4-epimerase from Pyrococcus horikoshii: Regeneration of UDP to produce UDP-galactose using two-enzyme system with trehalose

► A new robust UDP-Glc 4-epimerase from Pyrococcus horikoshii (pGALE) was characterized. ► pGALE showed re-usability, and was inhibited by a high concentration of UDP. ► One-pot two-enzyme system with pGALE and TreT was developed to complete a cycle. ► UDP was converted to produce UDP-Gal in the coupled reaction with trehalose fuel.