Reaction catalyzed by sepiapterin reductase (L-erythro-7,8-dihydrobiopterin forming) (1.1.1.153)
+
NADPH
+
=
+
NADP+
lactoyltetrahydropterin
+
NADPH
+
H+
=
L-erythro-tetrahydrobiopterin
+
NADP+
