Reaction catalyzed by vitamin D3 24-hydroxylase (1.14.15.16)
+
2
reduced adrenodoxin
+
2
+
=
+
2
+
H2O
3-epi-25,26,27-trinor-23-ene-1alpha-hydroxyvitamin D3
+
2 reduced adrenodoxin
+
2 H+
+
O2
=
3-epi-25,26,27-trinor-23,24-epoxide-1alpha-hydroxyvitamin D3
+
2 oxidized adrenodoxin
+
H2O
