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The case of the missing NO-hemoglobin: spectral changes suggestive of heme redox reactions reflect changes in NO-heme geometry.

Publication ,  Journal Article
Fago, A; Crumbliss, AL; Peterson, J; Pearce, LL; Bonaventura, C
Published in: Proceedings of the National Academy of Sciences of the United States of America
October 2003

When low levels of gaseous nitric oxide (NO) are equilibrated with deoxygenated Hb, all NO added can be accounted for in terms of hexacoordinate and pentacoordinate forms of NO-Hb, despite recent reports on NO disappearance from heme groups to form nitroxyl anions or S-nitrosated Hb at low ratios of NO to Hb. We demonstrate that a fraction of the spectral signature of fully nitrosylated (largely hexacoordinate) Hb disappears as the pentacoordinate state forms and reappears when pentacoordinate NO-Hb is reconverted to the hexacoordinate condition. We show that the spectral changes associated with these reversible shifts in NO- heme geometry can be remarkably well approximated as variations in the contributions from fully nitrosylated Hb and oxidized Hb (MetHb). As a result, increases in the level of pentacoordinate NO-Hb that occur at low NO to Hb ratios can be misinterpreted as increases in MetHb levels associated with NO-dependent heme oxidation. Conversely, any decrease in levels of pentacoordinate NO-Hb can be misinterpreted as a disappearance of MetHb associated with NO-dependent heme reduction. Transitions between pentacoordinate and hexacoordinate forms of NO-Hb with spectral changes suggestive of changes in levels of heme-bound NO are sensitive to the protein's quaternary conformation and can be brought about by alterations in anion levels or the degree of heme saturation with either O2 or NO.

Duke Scholars

Published In

Proceedings of the National Academy of Sciences of the United States of America

DOI

EISSN

1091-6490

ISSN

0027-8424

Publication Date

October 2003

Volume

100

Issue

21

Start / End Page

12087 / 12092

Related Subject Headings

  • Spectrophotometry
  • Oxidation-Reduction
  • Nitric Oxide
  • Methemoglobin
  • Kinetics
  • In Vitro Techniques
  • Humans
  • Hemoglobins
  • Heme
  • Glycated Hemoglobin
 

Citation

APA
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MLA
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Fago, A., Crumbliss, A. L., Peterson, J., Pearce, L. L., & Bonaventura, C. (2003). The case of the missing NO-hemoglobin: spectral changes suggestive of heme redox reactions reflect changes in NO-heme geometry. Proceedings of the National Academy of Sciences of the United States of America, 100(21), 12087–12092. https://doi.org/10.1073/pnas.2032603100
Fago, Angela, Alvin L. Crumbliss, Jim Peterson, Linda L. Pearce, and Celia Bonaventura. “The case of the missing NO-hemoglobin: spectral changes suggestive of heme redox reactions reflect changes in NO-heme geometry.Proceedings of the National Academy of Sciences of the United States of America 100, no. 21 (October 2003): 12087–92. https://doi.org/10.1073/pnas.2032603100.
Fago A, Crumbliss AL, Peterson J, Pearce LL, Bonaventura C. The case of the missing NO-hemoglobin: spectral changes suggestive of heme redox reactions reflect changes in NO-heme geometry. Proceedings of the National Academy of Sciences of the United States of America. 2003 Oct;100(21):12087–92.
Fago, Angela, et al. “The case of the missing NO-hemoglobin: spectral changes suggestive of heme redox reactions reflect changes in NO-heme geometry.Proceedings of the National Academy of Sciences of the United States of America, vol. 100, no. 21, Oct. 2003, pp. 12087–92. Epmc, doi:10.1073/pnas.2032603100.
Fago A, Crumbliss AL, Peterson J, Pearce LL, Bonaventura C. The case of the missing NO-hemoglobin: spectral changes suggestive of heme redox reactions reflect changes in NO-heme geometry. Proceedings of the National Academy of Sciences of the United States of America. 2003 Oct;100(21):12087–12092.
Journal cover image

Published In

Proceedings of the National Academy of Sciences of the United States of America

DOI

EISSN

1091-6490

ISSN

0027-8424

Publication Date

October 2003

Volume

100

Issue

21

Start / End Page

12087 / 12092

Related Subject Headings

  • Spectrophotometry
  • Oxidation-Reduction
  • Nitric Oxide
  • Methemoglobin
  • Kinetics
  • In Vitro Techniques
  • Humans
  • Hemoglobins
  • Heme
  • Glycated Hemoglobin