Reaction catalyzed by 6-carboxytetrahydropterin synthase (4.1.2.50)
+
H2O
=
+
+
7,8-dihydroneopterin 3'-triphosphate
+
H2O
=
6-carboxy-5,6,7,8-tetrahydropterin
+
acetaldehyde
+
triphosphate
