   1.7.99.4 | physiological function |
under nitrate-rich conditions, the nar and nap genes encoding a membrane-bound form and a periplasmic form of nitrate reductase, as well as NO-regulated genes encoding flavohaemoglobin, flavorubredoxin and hybrid cluster protein are induced following transition from the oxic to anoxic state, and 20% of nitrate consumed in steady-state is released as N2O when nitrite has accumulated to millimolar levels. The kinetics of nitrate consumption, nitrite accumulation and N2O production are similar to those of wild-type in nitrate-sufficient cultures of a nap mutant. Under nitrate-limited conditions, periplasmic enzyme nap, but not nar, is upregulated following transition from oxic to anoxic metabolism and very little N2O production was observedA combination of nitrate-sufficiency, nitrite accumulation and an active Nar-type nitrate reductase leads to NO and thence N2O production, and this can account for up to 20% of the nitrate catabolized |
724233 |
