Enzymatic basis for the active transport of sodium and potassium across the cell membrane.

Skou discovered that the active transport of sodium and potassium is carried out in the cell membrane by an enzyme that serves as a sodium and potassium "pump," that catalyzes ATP hydrolysis. He named the enzyme
"sodium and potassium ATPase."

In 1997 Jens Skou shared the Nobel Prize in Chemistry with Paul D. Boyer and John E. Walker "for the first discovery of an ion-transporting enzyme, Na+, K+ -ATPase.”

(Thanks to Juan Weiss for this reference and its interpretation.)