Assimilatory nitrate reductase (catalytic subunit); Nitrate reductase is a key enzyme involved in the first step of nitrate assimilation in plants, fungi and bacteria.

Assimilatory nitrate reductase (electron transfer subunit NasB); Required for nitrate assimilation.

Nitrate reductase (beta subunit); The beta chain is an electron transfer unit containing four cysteine clusters involved in the formation of iron-sulfur centers. Electrons are transferred from the gamma chain to the molybdenum cofactor of the alpha subunit.

Assimilatory nitrite reductase subunit; Required for nitrite assimilation.

Assimilatory nitrite reductase subunit; Required for nitrite assimilation. Required for activity of the reductase (By similarity).

Nitrate reductase (gamma subunit); The gamma chain is a membrane-embedded heme-iron unit resembling cytochrome b, which transfers electrons from quinones to the beta subunit.

Nitrite extrusion permease; Involved in excretion of nitrite produced by the dissimilatory reduction of nitrate; Belongs to the major facilitator superfamily. Nitrate/nitrite porter (TC 2.A.1.8) family.

Ammonium transporter; Functions as an ammonium and methylammonium transporter in the absence of glutamine. Required for ammonium utilization at low concentrations or at low pH values, when ammonium is the single nitrogen source. Required for binding of NrgB to the membrane. Interaction between GlnK-AmtB complex and TnrA protects TnrA from proteolytic degradation.

Putative anionic nitroalkane dioxygenase; Nitronate monooxygenase that uses molecular oxygen to catalyze the oxidative denitrification of alkyl nitronates. Acts on propionate 3-nitronate (P3N), the presumed physiological substrate. Probably functions in the detoxification of P3N, a metabolic poison produced by plants and fungi as a defense mechanism.