Singlet oxygen. Suppresion of its production in dismutation of superoxide ion by superoxide dismutase

Singlet Molecular Oxygen and Superoxide Radical Anion

“…1) and only the latter form acts as a singlet oxygen quencher, the acid dissociation constant of the perhydroxyl radical pK =4.88 [24] , indicate that at biological pH the radical exists mainly in the dissociated form. It is possible however that high concentrations of very good singlet oxygen acceptors may reduce the amount of quenching and chemically trap some of the singlet oxygen generated [3] .…”

“…Calculation of the free energies of these reactions suggests that O 2 e~) is energetically accesible by this route and experimental support for this assumption has been provided [3]. Singlet molecular oxygen 02eAg) is a very powerful and specific oxidant whose chemical action is related to harmful biological effects such as the photodynamic effect, hemolysis of erythrocytes, sensitization of the human skin, destruction of the enzymes and nucleic acids, etc.…”

Polypyrrole–methylene blue nanoparticles as a single multifunctional nanoplatform for near-infrared photo-induced therapy and photoacoustic imaging

“…DPBF interacts with 1 O 2 and converts to o-dibenzoylbenzene (DBB). 25 The amount of DPBF consumption can be monitored by measuring the absorbance at 418 nm. In other words, the decrease of the UV-Vis absorption of DPBF at 418 nm indicated the 1 O 2 generation of the sample.…”

Sterol Metabolism. Xlii. On the Interception of Singlet Molecular Oxygen by Sterols

“…However, the oxidation of 1 to 3 also occurs in a slow process involving ground state molecular oxygen (302) of the air (Guyot and Catel, 1906;LeBerre and Ratsimbazafy, 1963;Mayeda and Bard, 1973). in reactions affected by trityl cation and '02 and by Tris-(pbromophenyl) ammoniumyl fluoroborate or hexachloroantimonate (Barton et al, 1975), in a photooxidation by processes not involving '02 (Wilson, 1966;Olmsted and Akashah, 1973;Mayeda and Bard, 1974). in free radical initiated processes (Howard and Mendenhall, 1975).…”

“…, 1975Rahimtula and OBrien, 1976) and with substrate H,O, (Rahimtula and O'Brien, 1976). Furthermore, although the furan l does not react with superoxide radical anion (0;) Bard, 1973, 1974;Nilsson and Kearns, 1974), unidentified products other than 3 are formed from 1 in reaction with hydrogen peroxide (Mayeda and Bard, 1974). Thus, although product analysis may differentiate reactions of 1 with peroxide from those with other dioxygen species, the approach obviously fails to distinguish among reactions of 1 with '02, ' 0 2 , peracids, or possibly other oxidizing species.…”