Novel biological function of sialic acid (N-acetylneuraminic acid) as a hydrogen peroxide scavenger.
We have found that N-acetylneuraminic acid (NANA) consumes toxic hydrogen peroxide (H(2)O(2)) under physiological conditions. Close investigation of this finding revealed that NANA was oxidized by an equimolar amount of H(2)O(2) to provide its decarboxylated product, 4-(acetylamino)-2,4-dideoxy-D-glycero-D-galacto-octonic acid (ADOA). To date, there have been little data on this reaction, and its physiological significance has not been discussed. Examining the detoxification of H(2)O(2) in cultured cells with NANA, we were able to confirm that the cell death caused by H(2)O(2) was suppressed by NANA in a dose-dependent manner. These results revealed a novel role for NANA as a reactive oxygen scavenger. It is known that terminal NANA residues are removed by neuraminidase and that free NANA molecules are recycled or degraded by enzymes. We propose that released monomeric NANA is the potent defense molecule against oxidative damage.
Iijima
Ryosuke
R
Faculty of Pharmaceutical Sciences, Teikyo University, Sagamiko, Tsukui-gun, Kanagawa 199-0195, Japan. ryo-iiji@pharm.teikyo-u.ac.jp
Takahashi
Hideyo
H
Namme
Rie
R
Ikegami
Shiro
S
Yamazaki
Masatoshi
M
D000818:Animals; D000975:Antioxidants; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D016166:Free Radical Scavengers / Q000378:metabolism*; D006861:Hydrogen Peroxide / Q000378:metabolism*; D007700:Kinetics; D051379:Mice; D019158:N-Acetylneuraminic Acid / Q000378:metabolism / Q000494:pharmacology / Q000502:physiology*; D010084:Oxidation-Reduction
D000975:Antioxidants; D016166:Free Radical Scavengers; D006861:Hydrogen Peroxide; D019158:N-Acetylneuraminic Acid