Case of the hidden assumptions

The Ogston “three point attachment” model to explain how proteins discriminate between d and l isomers was originally proposed to explain the asymmetric distribution of isotopes that passed through a symmetric intermediate. It has been a standard in textbooks and the literature until the recent finding of Mesecar and Koshland [ 6 ] that it could not explain data of isocitrate dehydrogenase and other enzymes and must be replaced by a “four location model.” The hidden assumptions that are part of the Ogston model are seen to be an interesting feature of the scientific method that can both advance and hinder scientific progress.