Description
Catalyses triphosphate elimination and an intramolecular redox reaction in the presence of Mg2+. It has been identified in human liver. This enzyme is involved in the de novo synthesis of tetrahydrobiopterin from GTP, with the other enzymes involved being EC 1.1.1.153 (sepiapterin reductase) and EC 3.5.4.16 (GTP cyclohydrolase I)