Oxigenio singlete : geração, detecção e efeitos foto e bioenergizados sobre xantina-oxidase

AUTOR(ES)
DATA DE PUBLICAÇÃO

1982

RESUMO

The singlet oxygen (DgO2) effect on Xanthine-oxidase activity generated by: a) photodynamic processes using methylene blue and eosin as sensitizer and b) bioenergized processes, using the folic acid/HRP/glutathione/ catalase/Mn/O2 system was studied. Xanthine-oxidase can be inactivated easily by singlet oxygen by both processes. Methylene blue generates OH•, H2O2 and O2• besides singlet oxygen. They were detected by the proper quenchers and traps, and they are also responsable for Xanthine-oxidase inactivation. Eosin produces at the same condition specifically singlet oxygen, so this sensitizer is a good model for the enzymatic system which generates only singlet oxygen. Xanthine-oxidase also was inactivated by singlet oxygen generated by folic acid system. It was found that Xanthine-oxidase acts as a competitive inhibitor with histidine, which is a singlet oxygen quencher,following the steady state method through the photon emission from the malonaldehyde/HRP/Mn /O2 system.

ASSUNTO(S)

oxigenio ativo bioquimica bioenergetica

ACESSO AO ARTIGO

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