Accession Number:

ADA275042

Title:

Nitric Oxide Interaction with Lactoferrin and Its Production by Macrophage Cells Studied by EPR and Spin Trapping

Descriptive Note:

Corporate Author:

ARMED FORCES RADIOBIOLOGY RESEARCH INST BETHESDA MD

Report Date:

1993-01-01

Pagination or Media Count:

12.0

Abstract:

The production of nitrate N03- and nitrite N02- from macrophage-derived NO- was studied using EPR and spin trapping. The formation of NO3- was determined via EPR in reactions involving the iron-binding protein, lactoferrin errin. The formation of NO2- was determined via EPRspin trapping in the reaction between NO2- and H2O2. Dissolved nitric oxide NO- was reacted with lactoferrin yielding an EPR spectrum 77 K different from the normal EPR spectrum obtained for lactoferrin, suggesting that NO- interacts with the ferric ions bound to lactoferrin forming a ferric-nitrosyl type complex. The EPR spectrum 77 K of this ferric-nitrosyl type complex was also observed in the supernatant fluid of macrophage cell suspensions following their stimulation with lipopolysaccharide LPS. During LPS stimulation of macrophages, these cells generate NO- which in turn produces NO3- and NO2- . The ferric-nitrosyl type complex is formed in a reaction mixture containing apolactoferrin and bicarbonate following the reaction of Fe2 with NO3- and NO-. Furthermore, in an acidic medium, NO2- reacts with H2O2 forming peroxynitrous acid HOONO which rapidly decomposes into hydroxyl radicals OH and the nitrogen dioxide NO2- radical.

Subject Categories:

  • Inorganic Chemistry
  • Atomic and Molecular Physics and Spectroscopy

Distribution Statement:

APPROVED FOR PUBLIC RELEASE