Question

Explain:

1)The lock and key hypothesis of Enzyme Action

2) Induced fit hypothesis

Points: 25

Answer 1

lock and lock theory of enzyme

Answer 2

1) In 1894 Emil Fischer put forth the lock and key hypothesis . In this hypothesis enzyme was reffered as lock and substrate was reffered as key. This specific action of enzyme with a single substrate can be explained using this hypothesis . Every enzyme has it's own specific active site thus, substrate having the specific shape complementary to the active site will only be able to bind with the enzyme's active site. 
2) Induced fit hypothesis for mode enzyme action is a modification of the lock and key mode on enzyme action.
According to this, enzymes are flexible structures and the active site is continuously reshaped by enzyme- substrate  interactions. This means that enzymes does not simply bind to a rigid active site and the amino acid side-chains of the active site mold into the precise positions to enable the enzyme to perform its function. 
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