Born in South Carolina, William Rose graduated from North Carolina's Davidson College and received his Ph.D. from Yale in 1911. After post-doctoral work in Germany, he taught at the University of Texas from 1913 to 1922, then joined the staff of the University of Illinois where he remained until his retirement in 1955.

Throughout his career, Rose centered most of his attention on the amino acids, the nitrogen-containing organic compounds found in all protein molecules. It was already well known, of course, that proteins were essential to life. Still, since the early 1900s, researchers were aware that not all proteins were equally valuable. In 1912, for instance, Frederick Gowland Hopkins had shown that the protein in corn, called zein, could not sustain life in laboratory rats if it was the sole protein fed to them. But if casein, the protein in milk, was added to their diet, the rats once again thrived...