Banda M J, Clark E J, Werb Z
J Clin Invest. 1985 Jun;75(6):1758-62. doi: 10.1172/JCI111887.
Rabbit alveolar macrophages were cultured in an environment conducive to the secretion of both reactive oxygen and proteinases, so that the relative importance of proteolytic and oxidative inactivation of alpha 1-proteinase inhibitor by alveolar macrophages could be evaluated. The inactivation of alpha 1-proteinase inhibitor was proportional to its proteolysis, and there was no detectable inactivation in the absence of proteolysis. Although the live macrophages were capable of secreting reactive oxygen, they did not inactivate alpha 1-proteinase inhibitor by oxidation. The inactivation of alpha 1-proteinase inhibitor by proteolysis was proportional to the secretion of elastinolytic activity by the alveolar macrophages. The inability of the alveolar macrophages to oxidize alpha 1-proteinase inhibitor was attributed to the methionine in the macrophages, in secreted proteins, and in the culture medium competing for oxidants. The data suggest that proteolytic inactivation of alpha 1-proteinase inhibitor may be important in vivo and that the methionine concentration in vivo may protect alpha 1-proteinase inhibitor from significant oxidative inactivation.
兔肺泡巨噬细胞在有利于活性氧和蛋白酶分泌的环境中培养，以便评估肺泡巨噬细胞对α1-蛋白酶抑制剂进行蛋白水解失活和氧化失活的相对重要性。α1-蛋白酶抑制剂的失活与其蛋白水解成比例，并且在没有蛋白水解的情况下未检测到失活。虽然活巨噬细胞能够分泌活性氧，但它们不会通过氧化使α1-蛋白酶抑制剂失活。α1-蛋白酶抑制剂通过蛋白水解的失活与肺泡巨噬细胞分泌的弹性蛋白酶活性成比例。肺泡巨噬细胞无法氧化α1-蛋白酶抑制剂归因于巨噬细胞、分泌蛋白和培养基中的甲硫氨酸竞争氧化剂。数据表明，α1-蛋白酶抑制剂的蛋白水解失活在体内可能很重要，并且体内甲硫氨酸浓度可能保护α1-蛋白酶抑制剂免受显著的氧化失活。
