Involvement of a serine esterase in oxidant‐mediated activation of phospholipase A2 in pulmonary endothelium

[摘要]

Exposure of bovine pulmonary arterial endothelial cells to 1 mM H₂O₂ stimulated associated TAME-esterase and PLA₂ activities. Pretreatment with the serine esterase inhibitors: PMSF (1 mM), DFP (1 mM), and α₁-PI (1 mg/ml) inhibited H₂O₂-induced stimulation of TAME-esterase and PLA₂ activities. The TAME-esterase and PLA₂ activities under H₂O₂ exposure were determined to be linearly correlated. Affinity labeling of the endothelial cell membrane with [³H]DFP demonstrated that the serine esterase resides in a protein having molecular weight of 29000 daltons (29 kDa) which is similar to that of elastase. Treatment of the endothelial cell homegenate with trypsin (1 μ/ml) also stimulated PLA₂ activity.

[学科分类] 生物化学/生物物理

[关键词] Serine esterase;Phospholipase A2;Hydrogen peroxide;Oxidant;Antiproteases;Trypsin;Endothelial cells;PMSF;phenylmethylsulfonyl fluoride;DEP;diisopropyl fluorophosphate;TAME;p-tosyl-L-arginine methylester;H2O2;hydrogen peroxide;α1-PI;alpha;proteinase inhibitor;AA;arachidonic acid;PBS;phosphate buffered saline;PLA2;Phospholipase A2