Component of the dammarane-type triterpene saponins (e.g. ginsenosides or panaxosides) biosynthetic pathway (PubMed:26032089). Glycosyltransferase that catalyzes the biosynthesis of ginsenoside F1 from protopanaxatriol (PPT) and the conversion of ginsenoside F1 to ginsenoside Rg1 (PubMed:26032089). Triggers C20-OH glycosylation of ginsenoside Rg3 to produce ginsenoside Rd (PubMed:26032089). Mediates the conversion of protopanaxadiol (PPD) to the ginsenoside compound K (PubMed:26032089). (20S)-protopanaxadiol + UDP-alpha-D-glucose = (20S)-ginsenoside C-K + H(+) + UDP (20S)-ginsenoside Rg3 + UDP-alpha-D-glucose = (20S)-ginsenoside Rd + H(+) + UDP (20S)-protopanaxatriol + UDP-alpha-D-glucose = (20S)-ginsenoside F1 + H(+) + UDP (20S)-ginsenoside F1 + UDP-alpha-D-glucose = (20S)-ginsenoside Rg1 + H(+) + UDP Secondary metabolite biosynthesis; terpenoid biosynthesis. Belongs to the UDP-glycosyltransferase family.