Glycosyltransferase that catalyzes the C-glucosylation of daidzein to puerarin (PubMed:28207970). Shows activity with the isoflavones daidzein and genistein, but has no activity towards flavonoids such as 2-hydroxynaringenin (PubMed:28207970). Can use UDP-glucose, but not UDP-galactose or UDP-glucuronic acid as sugar donor (PubMed:28207970). Does not require bivalent cations for activity (PubMed:28207970). Inhibited by Cu(2+) or Zn(2+). kcat is 0.35 sec(-1) with daidzein as substrate. kcat is 0.45 sec(-1) with genistein as substrate. Optimum pH is 8.0. Belongs to the UDP-glycosyltransferase family.