Nitroalkane oxidase (NAO) catalyzes the oxidation of nitroalkanes to the corresponding aldehydes or ketones with the release of nitrite and the consumption of molecular oxygen to yield hydrogen peroxide (PubMed:20481475). NAO is unusual, since it catalyzes substrate oxidation by removing a substrate proton to form a carbanion intermediate (PubMed:20481475). Prefers longer nitroalkanes, with 1-nitrohexane having the highest activity (PubMed:20481475). a primary nitroalkane + H2O + O2 = an aldehyde + H(+) + H2O2 + nitrite a secondary nitroalkane + H2O + O2 = a ketone + H(+) + H2O2 + nitrite Optimally active at alkaline pHs. Homotetramer. Belongs to the acyl-CoA dehydrogenase family.