EC Explorer

1.14.16.1

phenylalanine 4-monooxygenase

L-phenylalanine + a 5,6,7,8-tetrahydropteridine + O₂ = L-tyrosine + a 4a-hydroxy-5,6,7,8-tetrahydropteridine

phenylalaninase, phenylalanine 4-hydroxylase, phenylalanine hydroxylase

L-phenylalanine,tetrahydropteridine:oxygen oxidoreductase (4-hydroxylating)

9029-73-6

The active centre contains mononuclear iron(II). The reaction involves an arene oxide that rearranges to give the phenolic hydroxy group. This results in the hydrogen at C-4 migrating to C-3 and in part being retained. This process is known as the NIH-shift. The 4a-hydroxytetrahydropteridine formed can dehydrate to 6,7-dihydropteridine, both spontaneously and by the action of EC 4.2.1.96, 4a-hydroxytetrahydrobiopterin dehydratase. The 6,7-dihydropteridine must be enzymically reduced back to tetrahydropteridine, by EC 1.5.1.34, 6,7-dihydropteridine reductase, before it slowly rearranges into the more stable but inactive compound 7,8-dihydropteridine.

created 1961 as EC 1.99.1.2, transferred 1965 to EC 1.14.3.1, transferred 1972 to EC 1.14.16.1, modified 2002, modified 2003, modified 2019