Who determined the molecular structure of penicillin?

Dorothy Crowfoot Hodgkin determined the molecular structure of penicillin. Working at Oxford, she used crystallographic data to confirm the compound’s three-dimensional arrangement, including its crucial beta-lactam ring.

The work built on a proposed structure from Edward Abraham and Ernst Boris Chain. Their proposal was controversial because many chemists doubted that penicillin could contain the strained four-membered beta-lactam ring. Hodgkin’s analysis provided decisive structural evidence in 1945.

This achievement was one of several major structure determinations by Hodgkin, who later solved vitamin B12 and made substantial progress on insulin. A common mix-up is to credit Alexander Fleming: Fleming discovered penicillin’s antibacterial activity, while Hodgkin determined its molecular structure decades later.