orotidine 5'-phosphate + diphosphate = orotate + 5-phospho-alpha-D-ribose 1-diphosphate
orotidine 5'-phosphate + diphosphate = orotate + 5-phospho-alpha-d-ribose 1-diphosphate
"orotidine-5'-phosphate diphosphorylase"
"orotidine-5'-phosphate diphosphorylase"