ExplorEnz: EC 1.17.3.4

1.17.3.4

Accepted name:

juglone 3-hydroxylase

Reaction:

2 juglone + O₂ = 2 3,5-dihydroxy-1,4-naphthoquinone (overall reaction)
(1a) 2 juglone + 2 H₂O = 2 naphthalene-1,2,4,8-tetrol
(1b) 2 naphthalene-1,2,4,8-tetrol + O₂ = 2 3,5-dihydroxy-1,4-naphthoquinone + 2 H₂O

Glossary:

juglone = 5-hydroxy-1,4-naphthoquinone

Other name(s):

juglone hydroxylase; naphthoquinone hydroxylase; naphthoquinone-hydroxylase

Systematic name:

5-hydroxy-1,4-naphthoquinone,water:oxygen oxidoreductase (3-hydroxylating)

Comments:

Even though oxygen is consumed, molecular oxygen is not incorporated into the product. Catalysis starts by incorporation of an oxygen atom from a water molecule into the substrate. The naphthalene-1,2,4,8-tetrol intermediate is then oxidized by molecular oxygen, which is reduced to water. Also acts on 1,4-naphthoquinone, naphthazarin and 2-chloro-1,4-naphthoquinone.

References:

1.	Rettenmaier, H. and Lingens, F. Purification and some properties of two isofunctional juglone hydroxylases from Pseudomonas putida J1. Biol. Chem. Hoppe-Seyler 366 (1985) 637–646. [PMID: 4041238]

[EC 1.17.3.4 created 1989 as EC 1.14.99.27, transferred 2016 to EC 1.17.3.4]