Factors affecting enzyme activity.

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Factors affecting Enzyme Activity

Enzymes are biological catalysts. Enzymes have specifically shaped active sites. The shape of the active site is complementary to the shape of the substrate molecules involved in the reaction. This means that the substrate molecules which are usually much smaller than the enzyme molecule, can fit into the active site. This is described as the lock and key hypothesis. This is because the substrate key fits into the active site lock. The substrate is then held in one place so the reaction can go ahead.

This allows the active site to fit more closely around the substrate, The substrate is held in place because of oppositely charged groups on the substrate and active site are located close to each other. This is known as an enzyme-substrate complex. Due to the change in shape of the enzyme, the substrate molecule is destabilised; this allows the reaction to go ahead with ease. This produces a product and is now known as an enzyme-product complex. These products that are formed are a different shape from the substrate. They do not fit into the active site in a complementary manner, therefore they move away. The enzyme now