How does the 'induced fit' model explain enzyme specificity?

The 'induced fit' model explains enzyme specificity by suggesting that enzymes change shape to fit specific substrates.

The 'induced fit' model is a refinement of the 'lock and key' model, which proposes that enzymes and substrates fit together perfectly like a lock and a key. However, the 'induced fit' model takes this a step further by suggesting that the enzyme's active site is flexible, not rigid. It changes shape in response to the substrate's presence, moulding itself around the substrate to achieve a perfect fit. This is why it's called 'induced fit' - the fit is 'induced' or brought about by the substrate's presence.

This model helps to explain enzyme specificity, which is the ability of an enzyme to select and catalyse a specific reaction. According to the 'induced fit' model, each enzyme is only able to catalyse a specific reaction because it can only change shape to fit specific substrates. If a substrate doesn't match the enzyme's active site, the enzyme won't be able to change shape to accommodate it, and the reaction won't be catalysed.

This model also explains why enzymes are so efficient. Because the enzyme changes shape to fit the substrate, it can hold the substrate in exactly the right position to catalyse the reaction. This reduces the amount of energy needed for the reaction to occur, making the enzyme a highly efficient catalyst.

In summary, the 'induced fit' model explains enzyme specificity by suggesting that enzymes are flexible, not rigid. They change shape to fit specific substrates, which allows them to select and catalyse specific reactions. This model also explains why enzymes are such efficient catalysts, as they can hold substrates in exactly the right position to catalyse reactions.