where the substrate fits into the enzyme and the active site and substrate have a complementary shape.
'lock and key' model
A) enzyme
B) substrate
C) active site
D) enzyme-substrate complex
E) enzyme-product complex
F) products
G) unchanged
Scientists soon realised that the lock and key model didn't give the full story.
The enzyme and substrate do have to fit together in the first place, but new evidence showed that the enzyme-substrate complex changed shape slightly to complete the fit. This locks the substrate even more tightly to the enzyme.
