Oxidant‐mediated proteolytic activation of Ca2+‐ATPase in microsomes of pulmonary smooth muscle

[摘要]

Treatment of bovine pulmonary artery smooth muscle tissue microsomes with H₂O₂ (1 mM) markedly stimulated protease activity tested with a synthetic substrate p-nitroanilide (BAPNA), and also enhanced Ca²⁺-ATPase activity. ATP-dependent Ca²⁺ uptake was found to be stimulated upon treatment of the microsomes with H₂O₂. Pretreatment of the microsomes with vitamin E and aprotinin prevented the H₂O₂-induced stimulation of Ca²⁺-ATPase activity and also ATP-dependent Ca²⁺ uptake. In contrast, H₂O₂-induced inhibition of Na⁺-dependent Ca²⁺ uptake was reversed by vitamin E and aprotinin.

[学科分类] 生物化学/生物物理

[关键词] Ca2+-ATPase;Protease;Aprotinin;Pulmonary smooth muscle tissue;Microsome;Oxidant;Hydrogen peroxide;HBPS;Hank's buffered physiological saline;BAPNA