Abstract
Soluble adenosine triphosphatases (ATPases) from carrot, beetroot, and the fresh-water alga Ohara australi8 were activated by sodium and potassium chlorides, but not by choline chloride, and were inhibited by potassium sulphate and fluoride. Ouabain was not inhibitory, and Na+-K+ synergism of the type found with animal "transport" ATPases was not observed.