Mechanisms of Enzyme Action: Lock and Key vs. Induced Fit

Enzyme-Substrate Complex:

·         Binding: 

                        An enzyme binds to its specific substrate, forming an enzyme-substrate (ES) complex.

·         Catalysis: 

                        The enzyme catalyzes the chemical reaction, transforming the substrate into products.

·         Dissociation: 

                        The ES complex dissociates, releasing the enzyme and products.

Models of Enzyme Action:

·         Lock and Key Model: 

                        Proposed by Emil Fischer, this model suggests that the enzyme and substrate have complementary shapes, fitting together like a lock and key.

·         Induced Fit Model: 

                       Proposed by Daniel Koshland, this model suggests that the active site of the enzyme is flexible and can change shape to accommodate the substrate.

Key Points:

·         Specificity: 

                    Enzymes are highly specific for their substrates due to the complementary shapes involved in the enzyme-substrate interaction.

·         Induced Fit: 

                    The induced fit model better explains the flexibility of enzymes and their ability to accommodate different substrates.

·         Active Site: 

                    The active site of the enzyme is the region where the substrate binds and the catalytic reaction occurs.

The induced fit model is generally considered to be a more accurate representation of enzyme action, as it accounts for the flexibility and adaptability of enzymes in recognizing and binding to their substrates.