William Howard Stein

William Howard Stein was born June 25, 1911, and spent his career unraveling the mechanics inside living cells. Working with collaborators, he determined the complete sequence of ribonuclease, an enzyme that breaks down RNA, then traced how its three-dimensional structure enables its catalytic function. That work earned him the Nobel Prize in Chemistry in 1972. Along the way, Stein helped invent the automatic amino acid analyzer, a machine that automated the tedious process of identifying amino acids in proteins and effectively birthed modern chromatography techniques — liquid, gas, the whole…