Enzyme Function and Activity

What are Enzymes?


Enzymes are molecules which catalyze chemical reactions. Enzyme molecules are large and globular and possess catalytic properties. Before modern discoveries all enzymes where thought to be proteins, but that belief was dismissed when some where proved to be made of RNA, however most enzymes are proteins. The configuration of an enzyme molecule is as a result of bonding such as hydrogen bonding, ionic bonding, disulphide bridges and hydrophobic interactions.

A Catalyst can alter the rate of a reaction without having itself undergo any permanent change. This therefore means that they can be used more than once.

Enzyme Function


In previous lessons we learned that the activation energy is the minimum energy required for a reaction to take place. Therefore reactions need to exceed their activation energy in order for them to take place. Enzymes reduce this need for activation energy thus allowing reactions to take place more readily.

It also reduces the temperature at which reactions take place thus allowing them to take place at temperatures lower than normal.

The lock and key mechanism refers to the way the substrate molds itself to fit into the active site of the enzyme in the same way a key fits a lock.

Terms you should know: 

Active site: - This is the part on the molecule of an enzyme into which the substrate fits.
Activation energy: - Minimum energy required for a reaction to take place.
Substrate: - The molecule at the beginning of a reaction that is later converted into products.
Specificity: - Enzymes are specific to reactions they catalyze and the substrates involved.

Enzyme Catalyzed Reaction