Approximately 25% of the circulating nitrates are taken up by the salivary glands where they are converted to nitrite by nitrate reductases
released from symbiotic bacteria in the oral cavity.
Demoss, "Nitrate reductases in Escherichia coli," Antonie van Leeuwenhoek, vol.
The nitrate reduction is associated with the bacterium's ability to breathe in the absence of oxygen and having two different metabolic pathways, (1) respiratory nitrate reductase and (2) dissimilatory nitrate reduction.
Among the Actinobacteria, respiratory nitrate reductase (Nar) is observed [15-18].
Relative abundances of proteobacterial membrane-bound and periplasmic nitrate reductases in selected environments.
It is reduced by nitrate reductase in assimilatory or dissimilatory way.
Many species of Campylobacter contain the nitrate reductase gene, such as Campylobacter jejuni, Campylobacter lari, Campylobacter concisus, Campylobacter fetus, and Campylobacter coli etc (Parkhill et al., 2000; Miller et al., 2008).
NITRATE REDUCTASE catalyzes the reduction of nitrate to nitrite, which is considered rate-limiting in nitrate assimilation in plants and nitrate-assimilating organisms (Beevers and Hageman, 1969; Solomonson and Barber, 1990).
Abbreviations: NR, nitrate reductase; NRA, nitrate reductase activity; DAT, days after transplanting.
Characteristics of a nitrate reductase in a barley mutant deficient in NADH nitrate reductase.
Enzymatic reduction of N[O.sub.3.sup.-] by using an immobilized Escherichia coli nitrate reductase column  converts ~30% of N[O.sub.3.sup.-] to N[O.sub.2.sup.-].
A spectrophotometric assay for nitrate using NADPH oxidation by Aspergillus nitrate reductase. Anal Biochem 1993;212:359-65.