Myoglobin: A scavenger of bioactive NO

Flogel, U.

doi:10.1073/pnas.011460298

Cited by 174 publications

(194 citation statements)

References 27 publications

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“…Separate experiments with only a one-time rather than a stepwise infusion of 100 nM and 1 μM bradykinin produce the same results. The observation matches the concentration-dependent response to bradykinin as reported in the literature [5,8,9,17].…”

Section: No and Mb Oxidationsupporting

confidence: 90%

“…These hyperfine-shifted metMb signals show about 15:1 signal to noise (S/N) ratio, quite comparable to the S/N of the reported −3.7 ppm peak [5]. Increasing the signal average by a factor of four yields a signal to noise ratio of 30:1 (data not shown).…”

Section: No and Mb Oxidationsupporting

confidence: 76%

“…With bradykinin infusion, perfusion pressure (PP) and rate pressure product (RPP) decrease, indicative of cellular NO formation. In perfused mouse heart, the previously reported 1 H NMR spectra show only one peak at −3.7 ppm [5]. In rat myocardium, experiments have not confirmed that observation and cannot detect either the −3.7 or −4.7 ppm peak during bradykinin stimulation.…”

Section: Introductionmentioning

confidence: 77%

“…In solution state experiments, metMb exhibits two peaks at −3.7 and −4.7 ppm. The reported data, however, show only one peak [5]. In hearts perfused with nitrite (NO 2 ), MbO 2 converts readily to metMb [3].…”

Section: Discussionmentioning

confidence: 92%

“…Recent studies have proposed a new role for Mb as a bioactive nitric oxide (NO) scavenger. The hypothesis predicates on the detection of a Fe(III) Mb [metmyoglobin (metMb)] reporter signal in isolated perfused mouse hearts during bradykinin stimulation [5]. Since bradykinin stimulates the production of NO, which can subsequently oxidize Mb to metMb, the presence of metMb implies a stoichiometric interaction of Mb with NO, in direct analogy to the interaction of NO with Hb [15].…”

Section: Introductionmentioning

confidence: 99%

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Investigation of bioactive NO-scavenging role of myoglobin in myocardium

Kreutzer

Jue

2006

Pflugers Arch - Eur J Physiol

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Because nitric oxide (NO) can react with myoglobin (Mb) to oxidize the heme Fe(II) to Fe(III), the appearance of metmyoglobin (metMb) during bradykinin stimulation underpins the hypothesis that Mb acts as an NO scavenger in the cell. Although some experiments have detected the reporter metMb signal in the -3.7 ppm spectral region, others have not corroborated the finding. Because metMb also has characteristic hyperfine-shifted signals in the 40-100 ppm spectral region, detection of these signals would confirm the presence of metMb. Perfused rat myocardium study has examined this spectral region in a range of bradykinin infusion protocols. Although bradykinin elicits a set of physiological responses, consistent with the induction of NO, the (1)H nuclear magnetic resonance spectra in all experiments reveal no detectable metMb signals. Moreover, in the perfused myocardium model, the bradykinin-induced decline in myocardial oxygen consumption does not appear to arise only from NO binding to cytochrome oxidase.

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Section: No and Mb Oxidationsupporting

confidence: 90%

Section: No and Mb Oxidationsupporting

confidence: 76%

Section: Introductionmentioning

confidence: 77%

Section: Discussionmentioning

confidence: 92%

Section: Introductionmentioning

confidence: 99%

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Investigation of bioactive NO-scavenging role of myoglobin in myocardium

Kreutzer

Jue

2006

Pflugers Arch - Eur J Physiol

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Iron: Heme Proteins & Dioxygen Transport & StorageBased in part on the article Iron: Heme Proteins & Dioxygen Transport by Harold M. Goff which appeared in theEncyclopedia of Inorganic Chemistry, First Edition.

Hayashi

2005

Encyclopedia of Inorganic and Bioinorganic Chemistry

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Most organisms require dioxygen (O 2 ) to survive; however, simple O 2 diffusion in blood does not supply a sufficient amount of oxygen for respiration. Thus, in all mammals, O 2 is carried and stored by O 2 ‐binding heme proteins, myoglobin, and hemoglobin. Myoglobin is a single‐chain globular protein with heme as a prosthetic group, while hemoglobin consists of four heme‐containing subunits. O 2 binds to ferrous pentacoordinated heme‐iron and is stabilized by distal and proximal amino acid residues in the heme pocket. The O 2 pathway in the protein matrix and the binding mechanisms are discussed in detail by O 2 ‐binding kinetic data for a series of myoglobin and hemoglobin mutants. Particularly, several residues, B10, E7, E10, E11, F7, and F8, mainly regulate the O 2 binding in the vertebrate heme proteins. In contrast, invertebrate and plant hemoglobins with unusually high O 2 affinities have been found in nature. In Ascaris hemoglobin, O 2 dissociation is very slow, whereas leghemoglobin shows a large O 2 association rate constant. In the case of trematode hemoglobin from Paramphistonum epiclitum , both kinetic parameters are improved. Artificial molecular design to modify O 2 affinity is another way to understand the O 2 binding mechanisms of the heme proteins. The strategy of heme protein modification can be divided into at least two approaches: One is a point mutation at distal or proximal amino acid residues, and the other is reconstitution by replacement of the native heme with an artificial heme. The physiological function of vertebrate hemoglobins is O 2 transport from the lungs or gills to the tissues; thus, they are required to exhibit cooperative interactions in binding O 2 to heme‐iron in the protein matrix. Although it is well known that a Hill coefficient of approximately 3.0 has been observed for tetrameric human hemoglobin, the mechanism of allosteric interaction is still discussed based on theoretical and experimental data. At present, an a two‐state (MWC) model proposed by Monod, Wyman, and Changeux for cooperative ligand binding is preferred to a sequential model. In addition, a study on the allosteric effectors for hemoglobins seems to be attractive from physiological aspects. The conventional effectors such as organic polyphosphate for human hemoglobin reduce the O 2 affinity of the T‐state, while it has been found that bezafibrate (BZF) or inositol hexaphosphate (IHP) can regulate O 2 binding not only for the T‐state but also for the R‐state. Finally, the interaction of NO with the heme proteins and modification of myoglobin for conversion into a new oxidase are briefly described.

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Molecular Ecophysiology of Antarctic Notothenioid Fishes

Cheng¹,

Detrich²

2012

Antarctic Ecosystems

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Myoglobin: A scavenger of bioactive NO

Cited by 174 publications

References 27 publications

Investigation of bioactive NO-scavenging role of myoglobin in myocardium

Investigation of bioactive NO-scavenging role of myoglobin in myocardium

Iron: Heme Proteins & Dioxygen Transport & StorageBased in part on the article Iron: Heme Proteins & Dioxygen Transport by Harold M. Goff which appeared in theEncyclopedia of Inorganic Chemistry, First Edition.

Molecular Ecophysiology of Antarctic Notothenioid Fishes

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