How Enzymes work

Enzymes work by intervening in chemical reactions by locking onto the substrate at their active site and speeding up the reaction. Enzymes can work in different ways, some enzymes help to break down large molecules into smaller ones, others build up large molecules from smaller ones whilst there are some that help change one molecule into another.

One of the fastest enzymes known is catalase. Catalase is found in many living cells and breaks down hydrogen peroxide into water and oxygen. Hydrogen peroxide is often formed as a product of reactions in cells, and can be poisonous if it builds up it is the job of catalase to remove the harmful hydrogen peroxide.




The substrate (hydrogen peroxide) and the enzyme (catalase) are continuously on the move. Every so often they collide so that the substrate molecule fits into the enzyme’s active site. Once in the active site the reaction takes place between the substrate and enzyme, the substrate is broken down into the two products (water and oxygen). When the required product has been produced, the enzyme releases itself and moves on. The enzyme is not used up in the reaction and so is ready to work again! No matter what job an enzyme does it will work in this similar way.