De novo pyrimidine biosynthesis, glutamine (+ PRPP) => UMP
Brite
Enzymatic reactions [BR:br08201]
1. Oxidoreductase reactions
1.3 Acting on the CH-CH group of donors
1.3.5 With a quinone or related compound as acceptor
1.3.5.2
R01868 (S)-Dihydroorotate + Quinone <=> Orotate + Hydroquinone