Modeling Hemoglobin Nitrite Reductase Activity as a Mechanism of Hypoxic Vasodilation?

2013 ◽  
pp. 361-368 ◽  
Author(s):  
Zimei Rong ◽  
Chris E. Cooper
Keyword(s):  
Nitrite Reductase ◽  
Reductase Activity ◽  
Nitrite Reductase Activity ◽  
Hypoxic Vasodilation

scholarly journals The functional nitrite reductase activity of the heme-globins

Blood ◽  
2008 ◽  
Vol 112 (7) ◽  
pp. 2636-2647 ◽  
Author(s):  
Mark T. Gladwin ◽  
Daniel B. Kim-Shapiro
Keyword(s):  
Small Molecules ◽  
Nitrite Reductase ◽  
Reductase Activity ◽  
Vital Role ◽  
Nitrite Reduction ◽  
Cellular Respiration ◽  
Oxygen Binding ◽  
Nitrite Reductase Activity ◽  
Hypoxic Vasodilation ◽  
Anaerobic Conversion

AbstractHemoglobin and myoglobin are among the most extensively studied proteins, and nitrite is one of the most studied small molecules. Recently, multiple physiologic studies have surprisingly revealed that nitrite represents a biologic reservoir of NO that can regulate hypoxic vasodilation, cellular respiration, and signaling. These studies suggest a vital role for deoxyhemoglobin- and deoxymyoglobin-dependent nitrite reduction. Biophysical and chemical analysis of the nitrite-deoxyhemoglobin reaction has revealed unexpected chemistries between nitrite and deoxyhemoglobin that may contribute to and facilitate hypoxic NO generation and signaling. The first is that hemoglobin is an allosterically regulated nitrite reductase, such that oxygen binding increases the rate of nitrite conversion to NO, a process termed R-state catalysis. The second chemical property is oxidative denitrosylation, a process by which the NO formed in the deoxyhemoglobin-nitrite reaction that binds to other deoxyhemes can be released due to heme oxidation, releasing free NO. Third, the reaction undergoes a nitrite reductase/anhydrase redox cycle that catalyzes the anaerobic conversion of 2 molecules of nitrite into dinitrogen trioxide (N2O3), an uncharged molecule that may be exported from the erythrocyte. We will review these reactions in the biologic framework of hypoxic signaling in blood and the heart.

scholarly journals 0099. Nitrite reductase activity during sepsis

2014 ◽  
Vol 2 (S1) ◽  
Author(s):  
V Simon ◽  
A Dyson ◽  
M Minnion ◽  
M Feelisch ◽  
M Singer
Keyword(s):  
Nitrite Reductase ◽  
Reductase Activity ◽  
Nitrite Reductase Activity

scholarly journals Nitrite Reductase Activity in Engineered Azurin Variants

2016 ◽  
Vol 55 (9) ◽  
pp. 4233-4247 ◽  
Author(s):  
Steven M. Berry ◽  
Jacob N. Strange ◽  
Erika L. Bladholm ◽  
Balabhadra Khatiwada ◽  
Christine G. Hedstrom ◽  
...  
Keyword(s):  
Nitrite Reductase ◽  
Reductase Activity ◽  
Nitrite Reductase Activity

scholarly journals Increased nitrite reductase activity of fetal versus adult ovine hemoglobin

2009 ◽  
Vol 296 (2) ◽  
pp. H237-H246 ◽  
Author(s):  
Arlin B. Blood ◽  
Mauro Tiso ◽  
Shilpa T. Verma ◽  
Jennifer Lo ◽  
Mahesh S. Joshi ◽  
...  
Keyword(s):  
Nitrite Reductase ◽  
Chronic Hypoxia ◽  
Reductase Activity ◽  
Fetal Hemoglobin ◽  
Nitrite Reduction ◽  
No Production ◽  
Low Oxygen ◽  
Nitrite Reductase Activity ◽  
Adult Hemoglobin ◽  
Severe Ischemia

Growing evidence indicates that nitrite, NO2−, serves as a circulating reservoir of nitric oxide (NO) bioactivity that is activated during physiological and pathological hypoxia. One of the intravascular mechanisms for nitrite conversion to NO is a chemical nitrite reductase activity of deoxyhemoglobin. The rate of NO production from this reaction is increased when hemoglobin is in the R conformation. Because the mammalian fetus exists in a low-oxygen environment compared with the adult and is exposed to episodes of severe ischemia during the normal birthing process, and because fetal hemoglobin assumes the R conformation more readily than adult hemoglobin, we hypothesized that nitrite reduction to NO may be enhanced in the fetal circulation. We found that the reaction was faster for fetal than maternal hemoglobin or blood and that the reactions were fastest at 50–80% oxygen saturation, consistent with an R-state catalysis that is predominant for fetal hemoglobin. Nitrite concentrations were similar in blood taken from chronically instrumented normoxic ewes and their fetuses but were elevated in response to chronic hypoxia. The findings suggest an augmented nitrite reductase activity of fetal hemoglobin and that the production of nitrite may participate in the regulation of vascular NO homeostasis in the fetus.

scholarly journals Inhibition of tobacco nitrite reductase activity by expression of antisense RNA.

1992 ◽  
Vol 2 (4) ◽  
pp. 559-569 ◽  
Author(s):  
H Vaucheret ◽  
J Kronenberger ◽  
A Lepingle ◽  
F Vilaine ◽  
JP Boutin ◽  
...  
Keyword(s):  
Nitrite Reductase ◽  
Antisense Rna ◽  
Reductase Activity ◽  
Nitrite Reductase Activity

scholarly journals The human B12 trafficking protein CblC processes nitrocobalamin

2020 ◽  
Vol 295 (28) ◽  
pp. 9630-9640 ◽  
Author(s):  
Romila Mascarenhas ◽  
Zhu Li ◽  
Carmen Gherasim ◽  
Markus Ruetz ◽  
Ruma Banerjee
Keyword(s):  
Nitrite Reductase ◽  
Reductase Activity ◽  
Methylmalonic Aciduria ◽  
Axial Ligand ◽  
Vitamin B ◽  
Early Step ◽  
Trafficking Pathway ◽  
Nitrite Reductase Activity ◽  
Futile Cycling ◽  
Thiol Oxidase

In humans, cobalamin or vitamin B12 is delivered to two target enzymes via a complex intracellular trafficking pathway comprising transporters and chaperones. CblC (or MMACHC) is a processing chaperone that catalyzes an early step in this trafficking pathway. CblC removes the upper axial ligand of cobalamin derivatives, forming an intermediate in the pathway that is subsequently converted to the active cofactor derivatives. Mutations in the cblC gene lead to methylmalonic aciduria and homocystinuria. Here, we report that nitrosylcobalamin (NOCbl), which was developed as an antiproliferative reagent, and is purported to cause cell death by virtue of releasing nitric oxide, is highly unstable in air and is rapidly oxidized to nitrocobalamin (NO2Cbl). We demonstrate that CblC catalyzes the GSH-dependent denitration of NO2Cbl forming 5-coordinate cob(II)alamin, which had one of two fates. It could be oxidized to aquo-cob(III)alamin or enter a futile thiol oxidase cycle forming GSH disulfide. Arg-161 in the active site of CblC suppressed the NO2Cbl-dependent thiol oxidase activity, whereas the disease-associated R161G variant stabilized cob(II)alamin and promoted futile cycling. We also report that CblC exhibits nitrite reductase activity, converting cob(I)alamin and nitrite to NOCbl. Finally, the denitration activity of CblC supported cell proliferation in the presence of NO2Cbl, which can serve as a cobalamin source. The newly described nitrite reductase and denitration activities of CblC extend its catalytic versatility, adding to its known decyanation and dealkylation activities. In summary, upon exposure to air, NOCbl is rapidly converted to NO2Cbl, which is a substrate for the B12 trafficking enzyme CblC.

Role of Nitrate in the Induction of Nitrite Reductase Activity during Wheat Seed Germination

1983 ◽  
Vol 34 (4) ◽  
pp. 396-404 ◽  
Author(s):  
ADITYA GUPTA ◽  
SUHAS DISA ◽  
INDER M. SAXENA ◽  
NEERA B. SARIN ◽  
SIPRA GUHA-MUKHERJEE ◽  
...  
Keyword(s):  
Seed Germination ◽  
Nitrite Reductase ◽  
Reductase Activity ◽  
Wheat Seed ◽  
Nitrite Reductase Activity

scholarly journals Modifying the Steric Properties in the Second Coordination Sphere of Designed Peptides Leads to Enhancement of Nitrite Reductase Activity

2018 ◽  
Vol 57 (15) ◽  
pp. 3954-3957 ◽  
Author(s):  
Karl J. Koebke ◽  
Fangting Yu ◽  
Elvin Salerno ◽  
Casey Van Stappen ◽  
Alison G. Tebo ◽  
...  
Keyword(s):  
Coordination Sphere ◽  
Nitrite Reductase ◽  
Reductase Activity ◽  
Nitrite Reductase Activity ◽  
Second Coordination Sphere

The nitrite reductase activity of ferrous human hemoglobin:haptoglobin 1-1 and 2-2 complexes

2018 ◽  
Vol 187 ◽  
pp. 116-122 ◽  
Author(s):  
Paolo Ascenzi ◽  
Grazia R. Tundo ◽  
Massimo Coletta
Keyword(s):  
Nitrite Reductase ◽  
Reductase Activity ◽  
Nitrite Reductase Activity
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