Localization and characterization of a parotid Ca(2+)-dependent ecto-ATPase.
Parotid acini were isolated and tested to further establish the presence of ecto-ATPase in the intact cells. Inhibitors were used to determine if the inhibitor profile of the ATPase was similar to that of a Ca(2+)-ATPase from parotid membranes identified previously as an ecto-ATPase. The Ca(2+)-ATPase of intact cells was insensitive to oligomycin (10 micrograms/ml), N-ethylmaleimide (NEM) (0.1 mM), ruthenium red (0.1 mM), sodium azide (1 mM), and was inhibited approximately 22% by sodium orthovanadate (Na3VO4) (1 mM). This profile was similar to the Ca(2+)-ATPase of intact cells. Trifluoperazine (TFP) (0.1 mM) inhibited the enzyme in intact cells by approximately 32%. The nucleotide substrate specificity of the enzyme also reflected very closely the pattern seen in isolated membranes.
Dowd
F J
FJ
Department of Pharmacology, School of Medicine, Creighton University, Omaha, NE 68178.
Li
L S
LS
Campbell
J E
JE
Cheung
P H
PH
D000251:Adenosine Triphosphatases / Q000037:antagonists & inhibitors / Q000302:isolation & purification / Q000378:metabolism*; D000818:Animals; D001386:Azides / Q000494:pharmacology; D000252:Calcium-Transporting ATPases / Q000037:antagonists & inhibitors / Q000302:isolation & purification / Q000378:metabolism*; D002462:Cell Membrane / Q000201:enzymology; D003570:Cytidine Triphosphate / Q000378:metabolism; D003979:Diazonium Compounds / Q000494:pharmacology; D005033:Ethylmaleimide / Q000494:pharmacology; D006160:Guanosine Triphosphate / Q000378:metabolism; D007293:Inosine Triphosphate / Q000378:metabolism; D010042:Ouabain / Q000494:pharmacology; D010306:Parotid Gland / Q000166:cytology / Q000201:enzymology* / Q000648:ultrastructure; D051381:Rats; D017207:Rats, Sprague-Dawley; D019810:Sodium Azide; D013425:Sulfanilic Acids / Q000494:pharmacology; D014268:Trifluoperazine / Q000494:pharmacology; D014638:Vanadates / Q000494:pharmacology
D001386:Azides; D003979:Diazonium Compounds; D013425:Sulfanilic Acids; D007293:Inosine Triphosphate; D014268:Trifluoperazine; D014638:Vanadates; D010042:Ouabain; D003570:Cytidine Triphosphate; D006160:Guanosine Triphosphate; D019810:Sodium Azide; D000251:Adenosine Triphosphatases; C027201:ectoATPase; D000252:Calcium-Transporting ATPases; D005033:Ethylmaleimide; C000469:diazobenzenesulfonic acid