SDS-PAGE (7.5%) of oxidized and native AAT incubated with human elastase. Lane 1, molecular size markers; lane 2, native (n) AAT; lane 3, native AAT + elastase incubated for 30 minutes at a molar ratio 1.2:1; lane 4, oxidized (ox) AAT; lane 5, oxidized AAT + elastase. Figure is characteristic of an experiment that was repeated twice, with identical results.