KEGG   ENZYME: 1.10.3.4Help
Entry
EC 1.10.3.4                 Enzyme                                 
Name
o-aminophenol oxidase;
isophenoxazine synthase;
o-aminophenol:O2 oxidoreductase;
2-aminophenol:O2 oxidoreductase;
GriF
Class
Oxidoreductases;
Acting on diphenols and related substances as donors;
With oxygen as acceptor
BRITE hierarchy
Sysname
2-aminophenol:oxygen oxidoreductase
Reaction(IUBMB)
2 2-aminophenol + O2 + acceptor = 2-aminophenoxazin-3-one + reduced acceptor + 2 H2O (overall reaction) [RN:R00074];
(1a) 2 2-aminophenol + O2 = 2 6-iminocyclohexa-2,4-dienone + 2 H2O [RN:R08762];
(1b) 2 6-iminocyclohexa-2,4-dienone + acceptor = 2-aminophenoxazin-3-one + reduced acceptor (spontaneous) [RN:R08763]
Reaction(KEGG)
Substrate
2-aminophenol [CPD:C01987];
O2 [CPD:C00007];
acceptor [CPD:C00028];
6-iminocyclohexa-2,4-dienone [CPD:C17500]
Product
2-aminophenoxazin-3-one [CPD:C02161];
reduced acceptor [CPD:C00030];
H2O [CPD:C00001];
6-iminocyclohexa-2,4-dienone [CPD:C17500]
Comment
A flavoprotein. While the enzyme from the plant Tecoma stans is activated by Mn2+ [1], that from the bacterium Streptomyces griseus (GriF) requires Cu2+ for maximal activity. Two molecules of the product 6-iminocyclohexa-2,4-dienone spontaneously condense with oxidation to yield 2-aminophenoxazin-3-one [4]. 3-Amino-4-hydroxybenzaldehyde, which has a -CHO group at the para-position with respect to the hydroxy group of 2-aminophenol, was found to be the best substrate for GriF [4].
Pathway
Tryptophan metabolism
Reference
1  [PMID:14170322]
  Authors
NAIR PM, VAIDYANATHAN CS.
  Title
ISOPHENOXAZINE SYNTHASE.
  Journal
Biochim. Biophys. Acta. 81 (1964) 507-16.
  Organism
Tecoma stans
Reference
2  [PMID:14298835]
  Authors
NAIR PM, VINING LC.
  Title
ESOPHENOXAZINE SYNTHASE APOENZYME FROM PYCNOPORUS COCCINEUS.
  Journal
Biochim. Biophys. Acta. 96 (1965) 318-27.
  Organism
Pycnoporus coccineus
Reference
3  [PMID:4166439]
  Authors
Subba Rao PV, Vaidyanathan CS.
  Title
Studies on the metabolism of o-aminophenol. Purification and properties of isophenoxazine synthase from Bauhenia monandra.
  Journal
Arch. Biochem. Biophys. 118 (1967) 388-94.
  Organism
Bauhenia monandra
Reference
4  [PMID:16282322]
  Authors
Suzuki H, Furusho Y, Higashi T, Ohnishi Y, Horinouchi S.
  Title
A novel o-aminophenol oxidase responsible for formation of the phenoxazinone chromophore of grixazone.
  Journal
J. Biol. Chem. 281 (2006) 824-33.
  Organism
Streptomyces griseus [GN:sgr]
Other DBs
ExplorEnz - The Enzyme Database: 
IUBMB Enzyme Nomenclature: 
ExPASy - ENZYME nomenclature database: 
BRENDA, the Enzyme Database: 
CAS: 
9013-85-8
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