May function as the terminal enzyme of the myo-inositol oxidation (MIO) pathway. May also play a role in the salvage pathway for synthesis of nucleotide sugars. a monosaccharide 1-phosphate + H(+) + UTP = a UDP-monosaccharide + diphosphate High activity with galactose-1-phosphate, glucose-1-phosphate or glucuronic acid-1-phosphate, but low or no activity with N-acetylglucosamine-1-phosphate, mannose-1-phosphate or glucose-6-phosphate. Optimum pH is 7.5-9.0. Expressed in root tips, young leaves, flowers and developing embryos. Belongs to the USP family.