Glycosyltransferase involved in the biosynthesis of kanamycins by catalyzing the transfer of the hexose kanosamine from UDP-alpha-D-kanosamine to disaccharide precursors. Can also use UDP-alpha-D-glucose as sugar donor with much lower efficiency. 2'-deamino-2'-hydroxyneamine + UDP-alpha-D-kanosamine = H(+) + kanamycin A + UDP neamine + UDP-alpha-D-kanosamine = H(+) + kanamycin B + UDP paromamine + UDP-alpha-D-kanosamine = H(+) + kanamycin C + UDP 2'-deamino-2'-hydroxyparomamine + UDP-alpha-D-kanosamine = H(+) + kanamycin X + UDP kcat is 3.36 min(-1) and 3.18 min(-1) for the reaction with paromamine as acceptor and UDP-alpha-D-kanosamine or UDP-alpha-D-glucose as donor, respectively. Antibiotic biosynthesis; kanamycin biosynthesis. Belongs to the glycosyltransferase group 1 family.