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Nitrite binding to globins: linkage isomerism, EPR silence and reductive chemistry.

Silaghi-Dumitrescu R, Svistunenko DA, Cioloboc D, Bischin C, Scurtu F, Cooper CE - Nitric Oxide (2014)

Bottom Line: We have used EPR (electron paramagnetic resonance) and DFT (density functional theory) to explore these binding modes to myoglobin and hemoglobin.The EPR and DFT data show that both nitrite linkage isomers can be present at the same time and that the two isomers are readily interconvertible in solution.The millisecond-scale process of nitrite reduction by Hb is investigated in search of the elusive Fe(II)-nitrite adduct.

View Article: PubMed Central - PubMed

Affiliation: "Babeş-Bolyai" University, 1 Mihail Kogalniceanu str., RO-400084 Cluj-Napoca, Romania; Department of Biological Sciences, University of Essex, Wivenhoe Park, Colchester, Essex CO4 3SQ, UK. Electronic address: rsilaghi@chem.ubbcluj.ro.

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Dependences on nitrite concentration for the two steps of the deoxy → met nitrite process discussed in Fig. 6. The rate constants are 0.08 M−1 s−1 for kl (A → B, black symbols in Fig.), and 0.04 M−1 s−1 for k2 (B → C, grey symbols); the reaction orders are 0.8 and 1, respectively. At nitrite concentrations below 400 mM, essentially no transformation of deoxy hemoglobin was observed under these conditions.
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f0045: Dependences on nitrite concentration for the two steps of the deoxy → met nitrite process discussed in Fig. 6. The rate constants are 0.08 M−1 s−1 for kl (A → B, black symbols in Fig.), and 0.04 M−1 s−1 for k2 (B → C, grey symbols); the reaction orders are 0.8 and 1, respectively. At nitrite concentrations below 400 mM, essentially no transformation of deoxy hemoglobin was observed under these conditions.

Mentions: Fig. 7 illustrates the dependences on nitrite concentration for the two steps of the oxy → met nitrite process discussed in Fig. 6. In line with our interpretation of the data, both processes depend on this concentration; the rate constants for the two consecutive processes are very similar to each other.


Nitrite binding to globins: linkage isomerism, EPR silence and reductive chemistry.

Silaghi-Dumitrescu R, Svistunenko DA, Cioloboc D, Bischin C, Scurtu F, Cooper CE - Nitric Oxide (2014)

Dependences on nitrite concentration for the two steps of the deoxy → met nitrite process discussed in Fig. 6. The rate constants are 0.08 M−1 s−1 for kl (A → B, black symbols in Fig.), and 0.04 M−1 s−1 for k2 (B → C, grey symbols); the reaction orders are 0.8 and 1, respectively. At nitrite concentrations below 400 mM, essentially no transformation of deoxy hemoglobin was observed under these conditions.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4256065&req=5

f0045: Dependences on nitrite concentration for the two steps of the deoxy → met nitrite process discussed in Fig. 6. The rate constants are 0.08 M−1 s−1 for kl (A → B, black symbols in Fig.), and 0.04 M−1 s−1 for k2 (B → C, grey symbols); the reaction orders are 0.8 and 1, respectively. At nitrite concentrations below 400 mM, essentially no transformation of deoxy hemoglobin was observed under these conditions.
Mentions: Fig. 7 illustrates the dependences on nitrite concentration for the two steps of the oxy → met nitrite process discussed in Fig. 6. In line with our interpretation of the data, both processes depend on this concentration; the rate constants for the two consecutive processes are very similar to each other.

Bottom Line: We have used EPR (electron paramagnetic resonance) and DFT (density functional theory) to explore these binding modes to myoglobin and hemoglobin.The EPR and DFT data show that both nitrite linkage isomers can be present at the same time and that the two isomers are readily interconvertible in solution.The millisecond-scale process of nitrite reduction by Hb is investigated in search of the elusive Fe(II)-nitrite adduct.

View Article: PubMed Central - PubMed

Affiliation: "Babeş-Bolyai" University, 1 Mihail Kogalniceanu str., RO-400084 Cluj-Napoca, Romania; Department of Biological Sciences, University of Essex, Wivenhoe Park, Colchester, Essex CO4 3SQ, UK. Electronic address: rsilaghi@chem.ubbcluj.ro.

Show MeSH
Related in: MedlinePlus