A flavoprotein which catalyses a 6-electron oxidation. The enzyme from the plant Tecoma stans requires Mn2+ and FAD  whereas the fungus Pycnoporus coccineus requires Mn2+ and riboflavin 5′-phosphate , the bacteria Streptomyces antibioticus requires Cu2+  and the plant Bauhenia monandra does not require any co-factors .
Nair, P.M. and Vining, L.C. Isophenoxazine synthase apoenzyme from Pycnoporus coccineus. Biochim. Biophys. Acta96 (1965) 318–327. [DOI] [PMID: 14298835]
Rao, P.V.S. and Vaidyanathan, C.S. Studies on the metabolism of o-aminophenol. Purification and properties of isophenoxazine synthase from Bauhenia monandra. Arch. Biochem. Biophys.118 (1967) 388–394. [DOI] [PMID: 4166439]
Barry, C.E., 3rd, Nayar, P.G. and Begley, T.P. Phenoxazinone synthase: mechanism for the formation of the phenoxazinone chromophore of actinomycin. Biochemistry28 (1989) 6323–6333. [PMID: 2477054]