Ecto-ATPases: Recent Progress on Structure and Function

It has been known for almost 50 years that many cells carry enzymes that hydro- lyze extracellular ATP, and the term "ecto-ATPase" was used first by Engelhardt 40 years ago. But until the end of the 1970's, the idea of an ATPase with its ATP hydrolyzing site on the outside of the cell membrane was met with substantial skepticism since it was thought that ATP was strictly intracellular. Nevertheless, ecto-ATPase activity was dem- onstrated using a variety of intact cells. Most ecto-ATPase(s)...