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

1. Subcellular fractions were prepared from the electric organs of Electrophorus and Torpedo and assayed for adenosine-triphosphatase activity. 2. Treatment of the ;low-speed' fraction from Torpedo with m-urea gave an adenosine-triphosphatase preparation that was almost completely (98%) inhibited by ouabain (0.1mg./ml.) and dependent on the simultaneous presence of Na(+) and K(+). 3. The adenosine-triphosphatase preparations were exposed to [gamma-(32)P]ATP for 30sec. in the presence of (i) Na(+), (ii) K(+), (iii) Na(+)+K(+) and (iv) Na(+)+K(+)+ouabain. No significant labelling of phosphatidic acid, triphosphoinositide or any other phospholipid was observed. 4. The results suggest that phospholipids do not act as phosphorylated intermediates in the ;transport adenosine-triphosphatase' system of electric organ.