The Nobel Prize in Chemistry 1975 was divided equally between John Warcup Cornforth "for his work on the stereochemistry of enzyme-catalyzed reactions" and Vladimir Prelog "for his research into the stereochemistry of organic molecules and reactions".
 

Cornforth's subject is concerned with the delicate mechanism of important reactions in biological systems, where a group of atoms takes the place of a certain hydrogen atom among two or three, which may appear to be equivalent. Professor Prelog's research spans a wide field. One area of study has been "medium-sized rings" - ring-shaped molecules with 8-12 carbon atoms. Another important area of his research is that concerned with chiral molecules, formerly called asymmetric molecules.