-Can be explained by induced fit hypothesis

-Enzymes have flexible active sites that is not complementary to substrates at ground level.

-Initial binding of substrates initiates interactions of functional grps between enzyme and substrate.

-Mutual interactions causes shape of enzyme active site to change.

-Enzyme changes from ground state to transition state.

-Catalytic residues properly aligned at the active site of enzyme molecules.

-Non-substrate cannot initiate same interactions, cannot catalyse. Hence this shows that enzymes are specific in their actions.

-Enzymes in transition state is complementary to substrate molecules.

-Different substrate can be catalyses by same enzyme, but not in the same activated forms.

-Binding of substrate to enzyme in correct orientation and effective collisions, form E-S complex, decreases activation energy of reaction.

-Rate of formation of E-S complexes depends on frequency of effective collisions between enzyme and substrates.