 PRPP also plays an important role in pyrimidine ribonucleotide synthesis.During the fifth step of pyrimidine nucleotide synthesis, PRPP covalently links to orotate at the one-position carbon on the ribose unit.The reaction is catalyzed by orotate phosphoriboseyltransferase (PRPP transferase), yielding orotidine monophosphate (OMP).