Nitric oxide (NO) generated through L-arginine metabolism by endothelial nitric oxide synthase (eNOS) is an important regulator of the vessel wall. Dysregulation of this system has been implicated in various pathological vascular conditions, including atherosclerosis, angiogenesis, arteriogenesis, neointimal hyperplasia, and pulmonary hypertension. The pathophysiology involves a decreased bioav...

A gene that encodes a periplasmic copper-type nitrite reductase (NirK) was identified in Nitrosomonas europaea. Disruption of this gene resulted in the disappearance of Nir activity in cell extracts. The nitrite tolerance of NirK-deficient cells was lower than that of wild-type cells. Unexpectedly, NirK-deficient cells still produced nitric oxide (NO) and nitrous oxide (N(2)O), the latter in gr...

Nitrate and nitrite are present in the human oral cavity. The main origin of these components is nitrate that is contained in leafy vegetables such as lettuce and spinach (Tamme et al., 2006). Ingested nitrate is absorbed into human body by the intestine, and part of the absorbed nitrate is secreted into the oral cavity as a component of saliva. In the oral cavity, nitrate is reduced to nitrite...

The human pathogen Neisseria meningitidis is capable of growth using the denitrification of nitrite to nitrous oxide under microaerobic conditions. This process is catalyzed by two reductases: nitrite reductase (encoded by aniA) and nitric oxide (NO) reductase (encoded by norB). Here, we show that in N. meningitidis MC58 norB is regulated by nitric oxide via the product of gene NMB0437 which en...

A rapid isocratic method of high performance liquid chromatography system (HPLC) with a glassy carbon working electrode of electrochemical detector is set up for quantitative detection of trace amount of nitrite ion (NO2) in aqueous protein containing cell lysate, cell media, plasma, serum, urine and other body fluids. The solid extraction reversed phase cartridges (Sep-pak) are used for deprot...

Influence of the protonation state guanidinium group, present in 2nd sphere an iron porphyrin complex, reduction nitrite to nitric oxide via {FeNO} 6 intermediate.

Unlike murine mononuclear phagocytes, human macrophages do not release high amounts of nitric oxide (NO) in vitro despite the presence of nitric oxide synthase (NOS). To determine whether this limited NO synthesis in vitro is due to limited availability of the NOS substrate L-arginine, and putative NOS inhibiting factors present in foetal serum preparations, both alveolar macrophages (AM) and m...

The major aetiological agent of human bacterial meningitis is Neisseria meningitidis. During the course of disease and host colonization, the bacterium has to withstand limited oxygen availability. Nitrogen oxide and nitrogen oxyanions are thought to be present, which may constitute an alternative sink for electrons from the N. meningitidis respiratory chain. A partial denitrification pathway i...

NrfB is a small pentahaem electron-transfer protein widely involved in the respiratory reduction of nitrite or nitric oxide to ammonia, processes that provide energy for anaerobic metabolism in many enteric bacteria and also serve to detoxify these reactive nitrogen species. The X-ray crystal structure of Escherichia coli NrfB is presented at 1.74 A (1 A=0.1 nm) resolution. The architecture of ...

Nitric oxide (NO) generated from nitrite through nitrite reductase activity in red blood cells has been proposed to play a major role in hypoxic vasodilation. However, we have previously predicted from mathematical modeling that much more NO can be derived from tissue nitrite reductase activity than from red blood cell nitrite reductase activity. Evidence in the literature suggests that tissue ...