Oxidation of Biologically Active Reducing Substances by Ozone

Publisher Website
Google Scholar
Abstract
Cysteine, reduced glutathione, thioglycolic acid, NADH and NADPH are readily oxidized by ozone. When glutathione is oxidized, the product is not reducible by the biological system of glutathione reductase and NADPH. NADH and NADPH are biologically active as coenzymes, however, after oxidation. Sulfhydryl enzymes, papain, and glyceraldehyde 3-phosphaîe dehydrogenase are also inactivated by ozone even in the presence of cysteine. The inactive form of the enzymes is only partially reactivated by cysteine. Other sulfhydryl reagents provide only partial protection of papain against ozone. Selenocysteine in combination with cysteine is a highly effective protector. These data suggest that ozone may act by oxidation of sulfhydryl compounds, and especially sulfhydryl enzymes, to higher oxidation states than the disulfide which is not reducible by the reductases available in cells. Seleno compounds may be important cellular protectors.