Danish biophysicist who with US biochemist Paul D Boyer and English chemist John Walker, shared the Nobel Prize for Chemistry in 1997 for his discovery of the enzyme sodium-potassium-activated-adenosine triphosphatase (Na+,K+−ATPase) that helps exchange sodium (Na+) for potassium (K+) through the plasma membrane of animal cells.
It had been known since the 1920s that the concentration of ions within living cells differs from their surroundings. Potassium ion (K+) concentration is always lower and sodium ion (Na+) concentration higher within the cell than in the surrounding liquid. Why this occurred or how the balance was maintained was not known. Adenosine triphosphate (ATP) was thought to play a crucial role in the mechanism for this process. Skou proposed that an enzyme based on ATP was responsible for ion transport. He studied nerve cell membranes taken from crabs and determined that the enzyme sodium-potassium-activated-adenosine triphosphatase (Na+,K+−ATPase) allowed ion transport to take place. This enzyme acts as an ion pump, transporting K+ into a cell and Na+ ions out, to maintain the ionic balance between the cell and its environment.
Skou's work resulted in the discovery of similar enzymes in a number of biological reactions and has led to advances in medical treatment. For example, the enzyme which controls the production of hydrochloric acid is the stomach is a calcium-based ion pump and modern treatments of stomach ulcers are based on the suppression of this enzyme. Ion pump enzymes are now commonly known as P-type ATPases since phosphorus is added to the molecule during the chemical reactions they take part in.
Skou was born in Lemvig, Denmark. He studied medicine at the University of Copenhagen and received his doctoral degree at Århus University in 1954, where he became professor of physiology in 1963. He was appointed professor of biophysics there in 1977.