sentences:  Orotate phosphoribosyltransferase
  
  Orotate phosphoribosyltransferase (OPRTase) or orotic acid phosphoribosyltransferase is an enzyme involved in pyrimidine biosynthesis.It catalyzes the formation of orotidine 5'-monophosphate (OMP) from orotate and phosphoribosyl pyrophosphate.