THE ADENOSINE-TRIPHOSPHATASE SYSTEM RESPONSIBLE FOR CATION TRANSPORT IN ELECTRIC ORGAN: EXCLUSION OF PHOSPHOLIPIDS AS INTERMEDIATES

Publisher Website
Google Scholar
Abstract
Subcellular fractions were prepared from the electric organs of Electrophorus and Torpedo and assayed for adenosine-triphosphatase (ATPase) activity. Treatment of the low-speed fraction from Torpedo with M-urea gave an ATPase preparation that was almost completely (98%) inhibited by ouabain (0-I mg/ml) and dependent on the simultaneous presence of Na+ and K+. The ATPase preparations were exposed to [<-P32] adenosine triphosphate for 30 sec. in the presence of Na+, K+, Na+ + K+ and Na+ + K+ + ouabain. No significant labeling of phosphatidic acid, triphos-phoinositide or any other phospholipid was observed. The results suggest that phospholipids do not act as phosphorylated intermediates in the transport ATPase system of electric organ.