According to the induced fit model of enzyme action, the active site
- A. is already an exact complement of the substrate before binding
- B. changes shape slightly as the substrate binds
- C. plays no part in catalysis
- D. binds any substrate regardless of shape
Explanation
Koshland's induced fit model replaced the rigid lock and key picture: the active site is flexible and moulds itself around the substrate as binding occurs, straining the bonds that are about to break. The lock and key model is the one that treats the site as pre-formed and rigid. Specificity is retained in both models, so an enzyme still does not bind just any substrate.