In enzymology, an UTP-monosaccharide-1-phosphate uridylyltransferase (EC 2.7.7.64) is an enzyme that catalyzes the chemical reaction

UTP + a monosaccharide 1-phosphate diphosphate + UDP-monosaccharide

Thus, the two substrates of this enzyme are UTP and monosaccharide 1-phosphate, whereas its two products are diphosphate and UDP-monosaccharide.

This enzyme belongs to the family of transferases, specifically those transferring phosphorus-containing nucleotide groups (nucleotidyltransferases). The systematic name of this enzyme class is '. Other names in common use include UDP-sugar pyrophosphorylase', and PsUSP.

• Tsumuraya Y; Yamaguchi, D; Ohzono, H; Hojo, S; Kaneko, S; Ishida, HK; Tsumuraya, Y (2004). "UDP-sugar pyrophosphorylase with broad substrate specificity toward various monosaccharide 1-phosphates from pea sprouts". J. Biol. Chem. 279 (44): 45728–36. doi:10.1074/jbc.M408716200. PMID 15326166.
• Rudick VL, Weisman RA (1974). "Uridine diphosphate glucose pyrophosphorylase of Acanthamoeba castellanii. Purification, kinetic, and developmental studies". J. Biol. Chem. 249 (24): 7832–40. PMID 4430676.