本文提到氢的问题,从自由基的角度分析氢的生物学效应

Forgotten Radicals in Biology
Rochette Luc, Catherine Vergely
Laboratoire De Physiopathologie Et Pharmacologie Cardiovasculaires Experimentales,
Facultes De Medecine Et Pharmacie, Dijon Cedex, France
Abstract
Redox reactions play key roles in intra- and inter-cellular signaling, and in adaptative processes of tissues
towards stress. Among the major free radicals with essential functions in cells are reactive oxygen species
(ROS) including superoxide anion (O2
•-), hydroxyl radical (•OH) and reactive nitrogen species (RNS) such as
nitric oxide (•NO). In this article, we review the forgotten and new radicals with potential relevance to cardiovascular
pathophysiology. Approximately 0.3% of O2
•- present in cytosol exists in its protonated form: hydroperoxyl
radical (HO2
•). Water (H2O) can be split into two free radicals: •OH and hydrogen radical (H•). Several
free radicals, including thiyl radicals (RS •) and nitrogen dioxide (NO2
•) are known to isomerize double
bonds. In the omega-6 series of poly-unsaturated fatty acids (PUFAs), cis-trans isomerization of γ-linolenate
and arachidonate catalyzed by RS • has been investigated. Evidence is emerging that hydrogen disulphide
(H2S) is a signaling molecule in vivo which can be a source of free radicals. The Cu-Zn superoxide dismutase
(SOD) enzyme can oxidize the ionized form of H2S to hydro-sulphide radical: HS•. Recent studies suggest
that H2S plays an important function in cardiovascular functions. Carbonate radical, which can be formed
when •OH reacts with carbonate or bicarbonate ions, is also involved in the activity of Cu-Zn-SOD. Recently,
it has been reported that carbonate anion were potentially relevant oxidants of nucleic acids in physiological
environments. In conclusion, there is solid evidence supporting the formation of many free radicals by cells
leading which may play an important role in their homeostasis. (Int J Biomed Sci 2008; 4(4):255-259)