Studies on the Generation of Electronic Excitation States in a Riboflavin-Hydrogen Peroxide-Copper-Ascorbate Redox System Leading to Chemiluminescence and/or Aromatic Hydroxylation^*

Abstract

Chemiluminescence in the visible spectrum is evidence that exothermic energies of from 45 to 80 kcal have been "coupled" to the generation of

The origin of the chemiluminescence of phagocytosing granulocytes.

“…Light emission is seen with many chemical oxidations, including the oxidations of simple aldehydes and ketones as well as of more complex compounds such as luminol (3-aminophthalhydrazide) and luciferin, the latter being the compound responsible for the luminescence of fireflies (37,38). Other compounds of biological importance have also been implicated in chemiluminescence: the breakdown of organic peroxides in the presence of metalloporphyrins has been shown to be associated with light emission (38), and Vohaben and Steele have described a light-emitting system consisting of H202, riboflavin, and ascorbic acid, the emission spectrum of which is very similar to the spectrum obtained in the present studies (39). With regard to tne oxidizing agent, chemiluminescence is typically observed in peroxide-mediated oxidations (37), but the singlet oxygenmediated cleavage of double bonds is also associated with light emission (see above), while the data reported in Table I suggests that 02i-utilizing reactions can result in the emission of light as well.…”

Erythrocuprein and singlet oxygen

“…Luminescence was observed with a Nuclear Chicago Model 725 liquid scintillation counter. The settings used were those suggested by Vorhaben and Steele [7] or Arneson [5] . The production of superoxide radicals was measured spectrophotometrically by the method of cytochrome c reduction [I].…”

Formation of methyl ester of 2-methylglyceric acid from thymine glycol residues: a convenient new method for determining radiation damage to DNA

“…Thus, radiolysis of water, Fenton's reagent (Uri, 1952), UV photolysis of hydrogen peroxide (Baxendale & Wilson, 1957), sonication, and treatment with ascorbate, CuS04, and hydrogen peroxide (Vorhaben & Steele, 1967;Wong et al, 1974;Ishimitsu et al, 1977) all produced thymine glycol residues presumably via hydroxyl radical attack. The assay with tritium-labeled borohydride was particularly sensitive, with untreated DNA giving an extremely small quantity of ester, about 5 cpm above background under the conditions specified.…”