In what ways does an enzyme speed up a reaction?

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dcbiostat eNotes educator| Certified Educator

Enzymes are proteins that act as catalysts to speed up the rate of a biochemical reaction. Some enzymes are specific to one reaction only, while most can act on multiple reactions with similar properties. This is because enzymes will match the shape of only specific substrate active sites. Although enzymes speed up chemical reactions, enzymes are not used up within the chemical reaction.

Enzymes speed up chemical reactions by lowering the activation energy of the chemical reaction. The activation energy is the amount of energy required to start a chemical reaction. If less energy is required to start the reaction, then the reaction will start faster.

Enzymes are able to lower the activation energy of a reaction by one of three ways:

1.      Providing an alternative pathway for the reaction.

2.      Stabilizing the transition state (substrate + enzyme complex) of a reaction.

3.      Destabilizing the substrate ground state of the reaction.