Functions as the terminal component of an NADH peroxidase (NADH:H(2)O(2) oxidoreductase) when using NADH:rubredoxin oxidoreductase (NROR) as the electron transport intermediary from NADH to RubY. H(+) + H2O2 + NADH = 2 H2O + NAD(+) Binds 3 Fe(3+) ions per subunit. Rubredoxin (Rd) increases the NADH consumption rate by serving as an intermediary electron-transfer shuttle between NROR and RubY. Homodimer. Various environmental stress conditions, e.g. oxidative stress (exposure to air or H(2)O(2)) and other stress factors such as salt, increased pH, high concentration of solvents or cold shock, do not lead to increased transcript levels of this gene. Is not repressed by PerR.