What is the active site of an enzyme?
The region into which the substrate fits.
What is special about the shape of the active site?
Active site shape is complementary to shape of substrate.
Charges are also complementary
What is the name for when an enzyme and subsrate bind together?
What is the original theory of enzyme action?
Lock and Key model
What does the Lock and Key Model say?
Active site is the Lock.
Substrate is the key
Both active site and subsrate are fixed in shape
What is the new theory for enzyme action?
What does the Induced Fit Hypothesis say?
Active site changes shape slightly to fit around substrate.
Analogy of hand and a glove
What is the first stage in an enzyme catalysed reaction?
Substrate fits into active site.
Enzyme-substrate complex formed.
What is the second stage in an enzyme catalysed reaction?
Active site changes shape to convert substrate into products.
Forms enzyme-product complex.
What is the third stage in an enzyme catalysed reaction?
Products no longer for active site.
Products are released.
What is the final stage in an enzyme catalysed reaction?
Active site is now free for another substrate molecule.