MT3/QR2 melatonin binding site does not use melatonin as a substrate or a co-substrate.
J Pineal Res
; 45(4): 524-31, 2008 Nov.
Article
em En
| MEDLINE
| ID: mdl-18826489
ABSTRACT
Quinone reductase 2 (QR2, E.C. 1.10.99.2) is implicated in cell reactive oxygen species production. The catalytic activity of this enzyme is inhibited by 1 microM of melatonin. QR2 was identified as the third melatonin binding site (MT3). It is of major importance to understand the exact roles of melatonin and QR2 in oxidative stress. A fascinating possibility that melatonin could serve as a co-substrate or substrate of QR2 was hypothesized recently. In the current investigation, nuclear magnetic resonance studies of the QR2 catalytic reaction were performed, the results led us to conclude that, whatever the conditions, melatonin is not cleaved off to form N1-acetyl-N2-formyl-5-methoxykynurenine by a catalytically active QR2, very strongly indicating that melatonin is neither a substrate nor a co-substrate of this enzyme. Further studies are needed in order to better understand the relationship between MT3/QR2, melatonin and redox status of the cells, in order to better explain the anti-oxidant activities of melatonin at pharmacological concentrations (>1 microM).
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Quinona Redutases
/
Cinuramina
/
Melatonina
Limite:
Humans
Idioma:
En
Revista:
J Pineal Res
Assunto da revista:
ENDOCRINOLOGIA
Ano de publicação:
2008
Tipo de documento:
Article
País de afiliação:
França