Effect of lipid peroxidation on Na+,K(+)-ATPase, 5'-nucleotidase and CNPase in mouse brain myelin.
In the presence of H2O2, solutions of Fe2+ were applied to brain homogenate and isolated myelin from adult SWV control mice and the shiverer dysmyelinating mutant mouse as a source of a reactive oxygen species (Fenton reaction). Under these conditions, lipid peroxidation was initiated and measured as thiobarbituric acid-reactive oxidation products (TBAR). This was accompanied by 85% inhibition of myelin-associated Na+,K(+)-ATPase and 25% inhibition of 5'-nucleotidase. In contrast, CNPase activity was not altered. Studies on the shiverer mutant brain revealed that in spite of hypomyelination and prevalence of premature, myelin-like membranes in the homogenate, the myelin-related enzymes reacted as normal enzymes to peroxidation. Differences in the resistance of Na+,K(+)-ATPase to peroxidation in the brain homogenate and myelin suggest that the myelin enzyme is extremely sensitive to reactive oxygen toxicity.
Domanska-Janik
K
K
Polish Academy of Sciences, Department of Neurochemistry, Warsaw.
Bourre
J M
JM
D015087:2',3'-Cyclic-Nucleotide Phosphodiesterases / Q000378:metabolism*; D015720:5'-Nucleotidase / Q000378:metabolism*; D000818:Animals; D001205:Ascorbic Acid / Q000494:pharmacology; D001921:Brain / Q000201:enzymology*; D005260:Female; D005290:Ferric Compounds / Q000494:pharmacology; D005296:Ferrous Compounds / Q000494:pharmacology; D006861:Hydrogen Peroxide / Q000494:pharmacology; D015227:Lipid Peroxidation; D008297:Male; D051379:Mice; D008818:Mice, Neurologic Mutants; D009186:Myelin Sheath / Q000201:enzymology*; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism*; D013858:Thiobarbiturates
D005290:Ferric Compounds; D005296:Ferrous Compounds; D013858:Thiobarbiturates; D006861:Hydrogen Peroxide; D015720:5'-Nucleotidase; D015087:2',3'-Cyclic-Nucleotide Phosphodiesterases; D000254:Sodium-Potassium-Exchanging ATPase; C029684:thiobarbituric acid; D001205:Ascorbic Acid