In superficially both the theories are similarly as the idea is that substrate plays a crucial role in determining the shape and that the structure of the enzyme is flexible in both theories. In both the theories, it suggested that a proper substrate can only induce or fit in the active site to form complex so it can start the function of the enzyme.
Both theories are very much similar however they have different approaches to its mechanical use in the reaction. In lock and key theory, it is said that the there is no need to change only a specific substrate fit where is in induces fit theory enzyme is flexible to fit the substrate to induce the activity.
In induced fit theory the active site is made of 2 components however in the lock and key theory the active site has 1 single entry.
