title: Detection of free radicals generated from hydrogen peroxide, gallic acid and haemoprotein chemiluminescence system by electron spin resonance spectroscopy.
abstract: Low-level chemiluminescence is produced in a hydrogen peroxide (H(2)O(2))/gallic acid/haemoprotein system with single broad peaks around 520 nm, regardless of the biological role of the haemoprotein. The free haem iron systems (haemin and haematin systems) gave a higher photon intensity (1.5 x 10(4) and 2.0 x 10(4) cps) than that of the H(2)O(2)/gallic acid/haematoporphyrin system. These results indicated that haem iron plays a significant role in the photon emission of haemoprotein systems. A free radical with a g value of 2. 0058 was detected through a direct electron spin resonance (ESR) method. The photon intensity of the H(2)O(2)/gallic acid/haemoprotein system decreased in the order: HRP > cytochrome c > myoglobin > haemoglobin, and this corresponded to the decrease in radical intensity. These results indicated that the formation of the free radical with a g value of 2.0058 may be the key step for chemiluminescence in the H(2)O(2)/gallic acid/haemoprotein system. A quartet line similar to DMPO-OH adducts and uncomplexed free radicals (g = 2.0058) was detected using the ESR spin-trapping method in the H(2)O(2)/gallic acid/cytochrome c system.
authors.affiliation: Department of Environmental Bioremediation, Graduate School of Agricultural Science, Tohoku University, 1-1 Tsutsumidori Amamiyamachi, Aoba-ku, Sendai, Miyagi, 981-8555, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Kawane
authors.forename: T
authors.initials: T
authors.lastname: Iida
authors.forename: Y
authors.initials: Y
authors.lastname: Yoshiki
authors.forename: K
authors.initials: K
authors.lastname: Okubo
authors.forename: M
authors.initials: M
authors.lastname: Tsunakawa
mesh_terms: D004578:Electron Spin Resonance Spectroscopy / Q000379:methods*; D005609:Free Radicals / Q000032:analysis*; D005707:Gallic Acid / Q000737:chemistry*; D006420:Hemeproteins / Q000737:chemistry*; D006427:Hemin / Q000737:chemistry; D006454:Hemoglobins / Q000737:chemistry; D006861:Hydrogen Peroxide / Q000737:chemistry*; D008163:Luminescent Measurements; D009211:Myoglobin / Q000737:chemistry
chemical_list: D005609:Free Radicals; D006420:Hemeproteins; D006454:Hemoglobins; D009211:Myoglobin; D005707:Gallic Acid; D006427:Hemin; D006861:Hydrogen Peroxide