·  Non-competitive inhibition

·  Uncompetitive inhibition

- the lock and key hypothesis is best described by competitive inhibition

- the inhibitor competes with the substrate for the enzyme’s active site, causing a decrease in the reaction rate

- the enzyme’s active site acts like a lock while the substrate is the key

- the inhibitor must have structure similar to the substrate to fit into the active site, thereby blocking the substrate from binding and preventing the reaction from occurring

1. Competitive inhibition

2. Non-competitive inhibition

3. Uncompetitive inhibition

The lock and key hypothesis described competitive inhibition. The active site of the enzyme act as lock for the competitive inhibitor (key) to bind to the active site. The competitive inhibitor (key) has match conformation as the enzyme active site. This will cause the substrate unable to bind to the enzyme active site.