4- nitrophenol monooxygenation

Nitrophenols — Monooxygenation is involved in the degradation of 4-nitrophenol by a strain of Moraxella sp. (Spain and Gibson 1991), and the enzyme appears to be a particulate flavoprotein. In the Gram-positive organisms Arthrobacter sp. (Jain et al. 1994) and Bacillus sphaericus strain JS905... 

For the degradation of 4-nitrophenol, two pathways that depend on the organism have been described, and both of them involve monooxygenation to quinones at different stages. This is analogous to that of 4-methyl-5-nitrocatechol, which is produced from 2,4-dinitrotolune and has already been described. 

Nishida et al. [42] reported formation of the monooxygenated product 16 in low yield together with quinone 6 by the reaction of 1 with Fe(HBPNP)Cl2 or Fe(BPA)Cl3 in nitromethane for 4 days, where HBPNP and BPA denote 2-[bis(2-pyridylmethyl)-aminomethyl]-4-nitrophenol and N,N-bis(2-pyridylmethyl)amine, respectively. 

Twenty five years after the initial observation of nitrite release from 4-nitrophenol the enzyme responsible for the reaction was partially purified from a Moraxella isolated from activated sludge (46). The nitrophenol oxygenase requires oxygen and reduced pyridine nucleotides for activity and is stimulated by the addition of flavin adenine dinucleotide. Experiments with 02 revealed that the reaction is a monooxygenation. The reaction requires the oxidation of two moles of NADPH for each mole of 4-nitrophenol converted to hydroquinone. The stoichiometry of the reaction suggests that the initial reaction produces... 

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