William Howard Stein

A biochemist who helped explain, at the level of individual atoms, how an enzyme actually works. Working with Stanford Moore, he mapped the complete amino acid sequence of ribonuclease and showed how its folded structure produces its catalytic activity, research that earned the two a share of the 1972 Nobel Prize in Chemistry. Along the way they helped invent the automatic amino acid analyzer, a chromatography advance that became a standard tool of modern biochemistry.