title: Oxidant-mediated proteolytic activation of Ca(+)-ATPase in microsomes of pulmonary smooth muscle.
abstract: Treatment of bovine pulmonary artery smooth muscle tissue microsomes with H2O2 (1 mM) markedly stimulated protease activity tested with a synthetic substrate N-benzoyl-DL-arginine p-nitroanilide (BAPNA), and also enhanced Ca(2+)-ATPase activity. ATP-dependent Ca(2+) 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 Ca(2+)-ATPase activity and also ATP-dependent Ca(2+) uptake. In contrast, H2O2-induced inhibition of Na(+)-dependent Ca(2+) uptake was reversed by vitamin E and aprotinin.
authors.affiliation: Department of Biochemistry and Biophysics, University of Kalyani, India.
authors.forename: S K
authors.initials: SK
authors.lastname: Ghosh
authors.forename: T
authors.initials: T
authors.lastname: Chakraborti
authors.forename: J R
authors.initials: JR
authors.lastname: Michael
authors.forename: S
authors.initials: S
authors.lastname: Chakraborti
mesh_terms: D015720:5'-Nucleotidase / Q000378:metabolism; D000135:Acid Phosphatase / Q000378:metabolism; D000818:Animals; D007611:Aprotinin / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism; D000252:Calcium-Transporting ATPases / Q000187:drug effects / Q000378:metabolism*; D002417:Cattle; D003576:Electron Transport Complex IV / Q000378:metabolism; D004789:Enzyme Activation; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D008861:Microsomes / Q000187:drug effects / Q000201:enzymology*; D009131:Muscle, Smooth, Vascular / Q000201:enzymology*; D009247:NADH, NADPH Oxidoreductases / Q000378:metabolism; D009251:NADPH-Ferrihemoprotein Reductase; D016877:Oxidants / Q000494:pharmacology*; D011651:Pulmonary Artery; D014810:Vitamin E / Q000494:pharmacology
chemical_list: D016877:Oxidants; D014810:Vitamin E; D007611:Aprotinin; D006861:Hydrogen Peroxide; D009247:NADH, NADPH Oxidoreductases; D009251:NADPH-Ferrihemoprotein Reductase; D003576:Electron Transport Complex IV; D000135:Acid Phosphatase; D015720:5'-Nucleotidase; D000252:Calcium-Transporting ATPases; D002118:Calcium