JoAnne Stubbe’s research has helped scientists understand the ways in which enzymes catalyze, or cause, chemical reactions. Professor Stubbe received the 2009 National Medal of Science, and is Novartis Professor of Chemistry and Professor of Biology at the Massachusetts Institute of Technology. Her major research efforts have focused on the mechanism of nucleotide reductases, the enzymes involved in the biosynthesis of deoxyribonucleic acid (DNA), the molecule of heredity. Her work has led to the design and synthesis of nucleotide analogs – structural derivatives of nucleotides – that have potential antitumor, antivirus, and antiparasite activity.