Protective effect of melatonin on photo-damage to lysozyme.
The behavior of melatonin in the riboflavin-sensitized photo-oxidation of lysozyme was monitored. Melatonin was found to prevent aggregation of protein and the decrease of enzyme activity induced by photo-oxidation. Electron spin resonance experiments showed that photo-oxidation of lysozyme in the presence of riboflavin resulted in formation of protein radicals, and melatonin was highly effective in reducing the formation of protein radicals. Direct evidence of melatonin's ability for quenching the triplet state of riboflavin and singlet oxygen was presented. A mechanism of the protective effect of melatonin on photo-oxidation of protein was proposed and the physiological relevance was discussed.
Zhu
Hongping
H
Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China. zhu@inorg.chem.ethz.ch
Chen
Shimou
S
Yao
Side
S
Wang
Wenfeng
W
D000818:Animals; D004789:Enzyme Activation / Q000187:drug effects / Q000528:radiation effects; D016166:Free Radical Scavengers / Q000378:metabolism / Q000494:pharmacology*; D005609:Free Radicals / Q000378:metabolism; D006801:Humans; D008027:Light / Q000009:adverse effects; D008550:Melatonin / Q000378:metabolism / Q000494:pharmacology*; D009113:Muramidase / Q000737:chemistry / Q000187:drug effects* / Q000378:metabolism / Q000528:radiation effects*; D010084:Oxidation-Reduction / Q000187:drug effects / Q000528:radiation effects; D018384:Oxidative Stress / Q000187:drug effects* / Q000528:radiation effects*; D055668:Photochemical Processes / Q000187:drug effects* / Q000528:radiation effects; D011485:Protein Binding / Q000187:drug effects / Q000528:radiation effects; D012256:Riboflavin / Q000494:pharmacology; D026082:Singlet Oxygen / Q000378:metabolism
D016166:Free Radical Scavengers; D005609:Free Radicals; D026082:Singlet Oxygen; D009113:Muramidase; D008550:Melatonin; D012256:Riboflavin