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CHEMILUMINESCENCE IN THE OXIDATION OF 6‐HYDROXYDOPAMINE: EFFECTS OF LUCIGENIN, SCAVENGERS OF ACTIVE OXYGEN, METAL CHELATORS AND THE PRESENCE OF OXYGEN
Author(s) -
Fatur Dolores J.,
San Richard H. C.,
Davison Allan J.,
Stich Hans F.
Publication year - 1987
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/j.1751-1097.1987.tb05395.x
Subject(s) - lucigenin , chemistry , hydroxydopamine , chemiluminescence , superoxide , superoxide dismutase , catalase , mannitol , luminescence , photochemistry , oxygen , ascorbic acid , nuclear chemistry , antioxidant , biochemistry , enzyme , organic chemistry , medicine , physics , food science , disease , pathology , optoelectronics , parkinson's disease
— Maximum chemiluminescence in a system containing 6‐hydroxydopamine (6‐OHDA) and H 2 O 2 required the addition of Fe 2+ :EDTA, oxygen, and lucigenin. In this system luminescence was strongly inhibited by catalase (91% inhibition) or 50 m M mannitol (83%), whereas superoxide dismutase or ascorbate did not significantly change the reaction rate. In the absence of lucigenin, 50 m M mannitol (78%), catalase (76%), or ascorbate (73%) inhibited strongly, while superoxide dismutase inhibited by 60%. Removing EDTA from the lucigenin‐containing system caused a 79% decrease in luminescence, while the substitution of desferoxamine for EDTA decreased luminescence by 55%. In the presence of desferoxamine plus EDTA the luminescence increased by 30% in comparison with that seen with EDTA alone. Luminescence in the system containing 6‐hydroxydopamine, H 2 O 2 , Fe 2+ :EDTA and lucigenin required the presence of oxygen (93% inhibition anaerobically), consistent with a mechanism involving reductive oxygenation of the lucigenin. It is concluded that luminescence in the presence of lucigenin involves a substantial contribution from H 2 O 2 and Fe 2+ mediated by a mannitol‐sensitive intermediate (conceivably Fenton‐derived hydroxyl radicals). In the absence of lucigenin, superoxide and an ascorbate‐labile component are additional important participants in the process.