UTP—hexose-1-phosphate uridylyltransferase () is an enzyme that catalyzes the chemical reaction
The enzyme characterised from Bifidobacterium bifidum and Entamoeba histolytica combines uridine triphosphate and galactose 1-phosphate to give uridine diphosphate galactose, with pyrophosphate (PPi) as a byproduct.
Nomenclature This enzyme is a transferase, specifically one transferring phosphorus-containing nucleotide groups (nucleotidyltransferases). The systematic name of this enzyme class is UTP:alpha-D-hexose-1-phosphate uridylyltransferase. Other names in common use include galactose-1-phosphate uridylyltransferase, galactose 1-phosphate uridylyltransferase, alpha-D-galactose 1-phosphate uridylyltransferase, galactose 1-phosphate uridyltransferase, UDPgalactose pyrophosphorylase, uridine diphosphate galactose pyrophosphorylase, and uridine diphosphogalactose pyrophosphorylase.
Structural studies , three structures have been solved for this class of enzymes, with PDB accession codes , , and .
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