Detection of free radicals generated from hydrogen peroxide, gallic acid and haemoprotein chemiluminescence system by electron spin resonance spectroscopy
✍ Scribed by Masaaki Kawane; Tetsuo Iida; Yumiko Yoshiki; Kazuyoshi Okubo; Mitsuaki Tsunakawa
- Publisher
- John Wiley and Sons
- Year
- 1999
- Tongue
- English
- Weight
- 70 KB
- Volume
- 14
- Category
- Article
- ISSN
- 1522-7235
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✦ Synopsis
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 Â 10 4 and 2.0 Â 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 b cytochrome c b myoglobin b 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.