Light-stimulated formation of hydrogen peroxide and hydroxyl radical in the presence of uroporphyrin and ascorbate

Journal Article · Fri Jan 01 00:00:00 EST 1988 · Free Radical Biology and Medicine; (USA)

DOI:https://doi.org/10.1016/0891-5849(88)90056-1· OSTI ID:5542656

Bachowski, G J; Girotti, A W ^[1]

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1. Medical College of Wisconsin, Milwaukee (USA)

Blue light irradiation of 2-deoxyribose (DOR) in the presence of uroporphyrin I (UP), ascorbate (AH-), trace iron, and phosphate buffer resulted in a strong stimulation of hydroxyl radical (OH.)-dependent oxidation of DOR. Photostimulated generation of H{sub 2}O{sub 2} was monitored after removal of residual AH- (i) by ascorbate oxidase treatment, or (ii) by anion exchange on mini-columns of DEAE-Sephadex. Irradiation of the above mixture produced a strong burst of H{sub 2}O{sub 2} which was intensified by desferrioxamine and suppressed by catalase or EDTA. The mechanism suggested by these observations is one in which photoreduction of UP to the radical anion initiates the formation of H{sub 2}O{sub 2}, which gives rise to OH. via Fenton chemistry. This is the first known investigation of H{sub 2}O{sub 2} fluxes in a Type I (free radical) photoreaction involving AH- as the electron donor.

• OSTI ID: 5542656
• Journal Information: Free Radical Biology and Medicine; (USA), Vol. 5:1; ISSN 0891-5849
• Country of Publication: United States
• Language: English

Related Subjects

63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
HYDROGEN PEROXIDE
BIOSYNTHESIS
RADICALS
ASCORBIC ACID
HYDROXIDES
ION EXCHANGE CHROMATOGRAPHY
PORPHYRINS
VISIBLE RADIATION
CARBOXYLIC ACIDS
CHROMATOGRAPHY
ELECTROMAGNETIC RADIATION
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
HYDROGEN COMPOUNDS
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
OXYGEN COMPOUNDS
PEROXIDES
RADIATIONS
SEPARATION PROCESSES
SYNTHESIS
VITAMINS
560300* - Chemicals Metabolism & Toxicology