Enzyme catalysis#Induced fit
The induced-fit theory ( " induced fit " ) explains the formation of a protein - ligand complex (eg, an enzyme -substrate complex in enzyme-catalyzed reactions).
It was postulated by Daniel E. Koshland in 1958 and is an extension of the key - lock principle: protein (eg, an enzyme ) and ligand (or substrate ) are no longer viewed as static. Both occur in proximity to interact and modify their conformations accordingly, resulting in only the protein -ligand complex can form.
However, this induced fit does not apply to all ligand -receptor complexes. The conformation of both partners are often natural limits, and so she often comes at the expense of specificity and affinity.