Synthesis of nitrogen oxides from L-arginine by macrophage cytosol: Requirement for inducible and constitutive components Academic Article uri icon

Overview

MeSH Major

  • Bone Neoplasms
  • Molecular Imaging
  • Positron-Emission Tomography
  • Prostatic Neoplasms

abstract

  • Cytosols prepared from murine peritoneal macrophages and the RAW 264 macrophage cell line catalyzed conversion of L-arginine to the labile vaso-relaxant nitric oxide and its accumulating endproducts, nitrite and nitrate. This activity required previous exposure of the cells to interferon-gamma and bacterial lipopolysaccharide. Nitrogen oxide synthetase activity was characterized further using nitrite + nitrate production as an indicator of the synthesis of all three nitrogen oxides. Nitrogen oxide synthetase activity was heat-sensitive, NADPH-dependent, and exhibited substrate stereospecificity. The nitrite + nitrate formation was proportional to time and concentration of cytosol. However, dilution decreased the specific activity, suggesting a cofactor requirement in addition to NADPH. Specific activity was restored by addition of cytosol from non-activated macrophages, which itself did not make nitric oxide. Both high and low molecular weight fractions of control macrophage cytosol were required to restore activity of cytosol from activated macrophages that had been either diluted or partially purified. Thus, the enzymatic system involved in nitric oxide synthesis by murine macrophages consists of at least one inducible and two constitutive components.

publication date

  • June 15, 1989

Research

keywords

  • Academic Article

Identity

Digital Object Identifier (DOI)

  • 10.1016/0006-291X(89)92615-6

Additional Document Info

start page

  • 420

end page

  • 6

volume

  • 161

number

  • 2