Characterization of a P-type copper-stimulated ATPase from mouse liver.
Mouse liver microsomes treated with octylthioglucoside (OTG-microsomes) were examined for copper-stimulated ATPase activity. The activity was about 1 micromol Pi/mg protein/hr under optimal conditions [300 mM KCl, 3 mm MgSO4, 10 mM GSH, 0.5 micron CuSO4, 3 mM ATP and 50 mM acetate buffer at pH5.0]. A reducing agent such as GSH or dithiothreitol was required for the activity, and removal of Cu+ from the reaction mixture by bathocuporinedisulfonate resulted in a complete loss of copper-stimulated ATPase activity. Vanadate inhibited the copper-stimulated ATPase activity. The OTG-microsomes were phosphorylated in a hydroxylamine-sensitive and copper-stimulated way. Iron used instead of copper also stimulated both ATPase and phosphorylation. These results suggest that microsomes from mouse liver contain copper/iron-stimulated P-type ATPase.
Takeda
K
K
Department of Biology, University of Occupational and Environmental Health, Kitakyushu 807-8555, Japan.
Ushimaru
M
M
Fukushima
Y
Y
Kawamura
M
M
D000251:Adenosine Triphosphatases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D000818:Animals; D003300:Copper / Q000494:pharmacology*; D003902:Detergents / Q000494:pharmacology; D007501:Iron / Q000494:pharmacology; D008099:Liver / Q000201:enzymology*; D051379:Mice; D008862:Microsomes, Liver / Q000201:enzymology; D010766:Phosphorylation / Q000187:drug effects; D013863:Thioglucosides / Q000494:pharmacology
D003902:Detergents; D013863:Thioglucosides; D003300:Copper; C042989:n-octyl-beta-D-thioglucopyranoside; D007501:Iron; D000251:Adenosine Triphosphatases