Effects of S-nitrosation on oxygen binding by normal and sickle cell hemoglobin.

Published

Journal Article

S-Nitrosated hemoglobin (SNO-Hb) is of interest because of the allosteric control of NO delivery from SNO-Hb made possible by the conformational differences between the R- and T-states of Hb. To better understand SNO-Hb, the oxygen binding properties of S-nitrosated forms of normal and sickle cell Hb were investigated. Spectral assays and electrospray ionization mass spectrometry were used to quantify the degree of S-nitrosation. Hb A(0) and unpolymerized Hb S exhibit similar shifts toward their R-state conformations in response to S-nitrosation, with increased oxygen affinity and decreased cooperativity. Responses to 2, 3-diphosphoglycerate were unaltered, indicating regional changes in the deoxy structure of SNO-Hb that accommodate NO adduction. A cycle of deoxygenation/reoxygenation does not cause loss of NO or appreciable heme oxidation. There is, however, appreciable loss of NO and heme oxidation when oxygen-binding experiments are carried out in the presence of glutathione. These results indicate that the in vivo stability of SNO-Hb and its associated vasoactivity depend on the abundance of thiols and other factors that influence transnitrosation reactions. The increased oxygen affinity and R-state character that result from S-nitrosation of Hb S would be expected to decrease its polymerization and thereby lessen the associated symptoms of sickle cell disease.

Full Text

Duke Authors

Cited Authors

  • Bonaventura, C; Ferruzzi, G; Tesh, S; Stevens, RD

Published Date

  • August 27, 1999

Published In

Volume / Issue

  • 274 / 35

Start / End Page

  • 24742 - 24748

PubMed ID

  • 10455144

Pubmed Central ID

  • 10455144

International Standard Serial Number (ISSN)

  • 0021-9258

Digital Object Identifier (DOI)

  • 10.1074/jbc.274.35.24742

Language

  • eng

Conference Location

  • United States