Nitrite May Be an Important EDRF Modulator.
Recently many studies suggested that S-nitrosothiols instead of active nitric oxide are EDRF. The studies showed that reduced thiols could not react directly with.NO at physiological pH (7.4) to form S-nitrosothiols but oxidized to nitrite which is very stable at pH 7.4. In contrast at low pH nitrite reacted rapidly with reduced thiols to form S-nitrosothiols. Similarly both nitrite and.NO gas reacted with deoxyHb and oxyHb at low pH but not at pH 7.4 to form HbFeII-NO complex or metHb and nitrate. The pH is a key factor to control this nitrosation process which is determined in vivo by oxygen tension and redox status. From these results a hypothesis is proposed that nitrite may be an EDRF modulator which controls the nitrosation level of reduced thiols in biological system.
Department of Clinical Biochemistry Chinese PLA General Hospital Beijing 100853 China. tianyp@plagh.com.cn
Ya-Ping
YP
Tian
M.
M
Rokicinski
W.H.
WH
Betts