Orotate phosphoribosyltransferase Tags: Enzyme.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. thumbnail EC number 2.4.2.10 Learn more... Loading...