Induced fit model was introduced because of the drawbacks of lock and key model. The lock and key model assumed that the active site is rigid having same conformation as that of substrate. So the question arises, how does an intermediate (Transition state of substrate) forms when the active site is rigid. The lock and key model failed to explain this phenomenon hence a new model called induced fit model as proposed. According to this model the active site of enzyme is not rigid with same conformation as that of substrate but the active site is flexible and can have different conformation. This model assumed that the amino acids present at the active site will determine the specific binding of substrate with the enzyme. Once the substrate binds the enzyme, the conformation of active site gradually changes and attains conformation as that of substrate molecule, hence it is called induced fit model.
![](https://s2.save4k.ru/pic/V8TOWTp71tE/mqdefault.jpg)