Nitric Oxide Interaction with Lactoferrin and Its Production by Macrophage Cells Studied by EPR and Spin Trapping
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 EPR/spin 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 Fe(+2) 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.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1993
- Accession Number
- ADA275042
Entities
People
- Alasdair J. Carmichael
- Brian Gray
- Carmen M. Arroyo
- Linda Steel-goodwin
Organizations
- Armed Forces Radiobiology Research Institute