How does the Lock-and-Key model relate to enzyme-substrate interactions?

The Lock-and-Key model explains how enzymes interact with specific substrates through complementary shapes.

Enzymes are biological catalysts that speed up chemical reactions in living organisms. They are highly specific, meaning that each enzyme can only catalyse one particular reaction. This specificity is due to the unique shape of the enzyme's active site, which is complementary to the shape of the substrate molecule it binds to. The Lock-and-Key model is used to explain this specificity.

In the Lock-and-Key model, the enzyme's active site is like a lock, and the substrate molecule is like a key. Just as a key can only fit into a specific lock, a substrate molecule can only fit into the active site of a specific enzyme. The two molecules have complementary shapes, and when they fit together, the enzyme can catalyse the reaction.

However, the Lock-and-Key model is not entirely accurate. It does not take into account the fact that enzymes are flexible and can change shape slightly to accommodate the substrate molecule. This is known as the Induced Fit model, which suggests that the enzyme and substrate undergo conformational changes upon binding to each other.

In conclusion, the Lock-and-Key model is a useful way to visualise how enzymes and substrates interact, but it is not the whole story. The Induced Fit model provides a more accurate representation of the enzyme-substrate interaction.