Reaction of ozone with protease inhibitors from bovine pancreas, egg white, and human serum

Abstract

Ozone inactivates the bovine pancreas trypsin-kallikrein inhibitor. Tyrosine and methionine residues are oxidized. When methionine is completely oxidized and 0.5 of the four tyrosine residues is oxidized, 90% of the inhibitor capacity is retained. When both methionine and tyrosine residues are completely oxidized, 37% of the inhibitor capacity is retained. For 50% loss of anti-trypsin activity, 62 moles of 0 3/mole of protein were required. Inhibition of the chicken ovomucoid proteinase inhibitor by ozone is accompanied by oxidation of tyrosine, histidine, and methionine residues. For 50% loss of anti-trypsin activity, 32 moles of O 3/mole of protein were required. Anti-trypsin activity of diluted human serum was only slightly inhibited by ozone. Purified α-1-antiprotease from human serum was 50% inactivated by 88 moles of O 3/mole of protein. The oxidation of free tyrosine by ozone proceeds by way of dihydroxyphenylalanine and dihydroxyphenylalanine quinone, finally yielding colored polymeric material.