Essential minerals

Keilin showed that the enzyme carbonic anhydrase contained a small quantity of zinc that was essential to its working. This meant that since the enzyme was essential to life, so was zinc. Other minerals associated with enzymes turned out to be required too, like manganese, molybdenum, and copper.
 David Keilin England 1939 Essential minerals

Keilin showed that the enzyme carbonic anhydrase contained a small quantity of zinc that was essential to its working. This meant that since the enzyme was essential to life, so was zinc. Other minerals associated with enzymes turned out to be required too, like manganese, molybdenum, and copper.