Involved in the biosynthesis of the cyanogenic glucoside dhurrin. Prevents the dissociation and release of toxic hydrogen cyanide. Mandelonitrile, p-hydroxymandelonitrile, benzyl alcohol, benzoic acid and geraniol, but not hydroquinone(1,4-benzenediol), alpha-terpinol, linalool or farnesol are utilized as acceptor substrates. UDP-glucose, but not UDP-xylose or UDP-glucuronic acid can be used as sugar donor. (S)-4-hydroxymandelonitrile + UDP-alpha-D-glucose = dhurrin + H(+) + UDP Inhibited by p-hydroxybenzaldehyde. Secondary metabolite biosynthesis; dhurrin biosynthesis; dhurrin from L-tyrosine: step 3/3. In the presence of CYP79A1 and CYP71E1, moves toward the surface of the ER membranes in order to form a metabolon. The N-terminus is partially blocked. Belongs to the UDP-glycosyltransferase family.