Spin trapping evidence for myeloperoxidase-dependent hydroxyl radical formation by human neutrophils and monocytes

Journal Article · Sat Apr 25 00:00:00 EDT 1992 · Journal of Biological Chemistry; (United States)

OSTI ID:5373979

Ramos, C L; Pou, S; Britigan, B E; Cohen, M S; Rosen, G M ^[1]

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1. Department of Pharmacology and Toxicology, University of Maryland School of Pharmacy, Baltimore (United States)

Using the electron spin resonance/spin trapping system, 4-pyridyl 1-oxide N-tert-butylnitrone (4-POBN)/ethanol, hydroxyl radical was detected as the alpha-hydroxyethyl spin trapped adduct of 4-POBN, 4-POBN-CH(CH3)OH, from phorbol 12-myristate 13-acetate-stimulated human neutrophils and monocytes without the addition of supplemental iron. 4-POBN-CH(CH3)OH was stable in the presence of a neutrophil-derived superoxide flux. Hydroxyl radical formation was inhibited by treatment with superoxide dismutase, catalase, and azide. Treatment with a series of transition metal chelators did not appreciably alter 4-POBN-CH(CH3)OH, which suggested that hydroxyl radical generation was mediated by a mechanism independent of the transition metal-catalyzed Haber-Weiss reaction. Kinetic differences between transition metal-dependent and -independent mechanisms of hydroxyl radical generation by stimulated neutrophils were demonstrated by a greater rate of 4-POBN-CH(CH3)-OH accumulation in the presence of supplemental iron. Detection of hydroxyl radical from stimulated monocyte-derived macrophages, which lack myeloperoxidase, required the addition of supplemental iron. The addition of purified myeloperoxidase to an enzymatic superoxide generating system resulted in the detection of hydroxyl radical that was dependent upon the presence of chloride and was inhibited by superoxide dismutase, catalase, and azide. These findings implicated the reaction of hypochlorous acid and superoxide to produce hydroxyl radical. 4-POBN-CH(CH3)OH was not observed upon stimulation of myeloperoxidase-deficient neutrophils, whereas addition of myeloperoxidase to the reaction mixture resulted in the detection of hydroxyl radical. These results support the ability of human neutrophils and monocytes to generate hydroxyl radical through a myeloperoxidase-dependent mechanism.

• OSTI ID: 5373979
• Journal Information: Journal of Biological Chemistry; (United States), Vol. 267:12; ISSN 0021-9258
• Country of Publication: United States
• Language: English

Related Subjects

63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
HYDROXYL RADICALS
BIOSYNTHESIS
PHORBOL ESTERS
BIOLOGICAL EFFECTS
CATALASE
ELECTRON SPIN RESONANCE
IRON
MACROPHAGES
MAN
MONOCYTES
NEUTROPHILS
NITROGEN OXIDES
SUPEROXIDE DISMUTASE
ANIMAL CELLS
ANIMALS
BIOLOGICAL MATERIALS
BLOOD
BLOOD CELLS
BODY FLUIDS
CARCINOGENS
CHALCOGENIDES
CONNECTIVE TISSUE CELLS
ELEMENTS
ENZYMES
ESTERS
LEUKOCYTES
MAGNETIC RESONANCE
MAMMALS
MATERIALS
METALS
NITROGEN COMPOUNDS
ORGANIC COMPOUNDS
OXIDES
OXIDOREDUCTASES
OXYGEN COMPOUNDS
PEROXIDASES
PHAGOCYTES
PRIMATES
PROTEINS
RADICALS
RESONANCE
SOMATIC CELLS
SYNTHESIS
TRANSITION ELEMENTS
VERTEBRATES
560300* - Chemicals Metabolism & Toxicology