Harden, Arthur (1865–1940)

English biochemist who shared the Nobel Prize for Chemistry in 1929 for his investigation of the mechanism of sugar fermentation and the role of enzymes in this process. He was knighted in 1936.

Harden was born in Manchester and studied at Owen's College (now the University of Manchester) and at Erlangen, Germany. He worked at the British Institute of Preventative Medicine (later called the Jenner Institute) from 1897 to 1912, when he became professor at the University of London.

Harden began work on sugar fermentation in 1898, investigating the metabolism of yeasts from 1900, three years after the discovery of enzymes. He showed that fermentation was caused by the action of the enzyme zymase on glycogen. Harden and his co-workers went on to show that zymase consists of at least two different substances: one heat-sensitive (probably a protein, the enzyme) and one heat-stable (now known as a coenzyme).

Harden then discovered the hexose sugar compound hexosediphosphate in the normal reaction mixture (he later found hexosemonophosphate as well), thus proving that phosphorylation is an intermediate step in the fermentation process. This finding stimulated great interest in intermediate metabolism.