Explain the lock and key model of enzyme action, including how they are denatured

The lock and key model refers to an analogy used to describe the specific action of an enzyme with a substrate . During this process, the enzyme is acting as the lock and has a section called the active site which is where the reaction will take place, and the substrate, for instance a protein, is the key. In the same way that a key is paired with a specific shape lock, substrates must fit the right shaped active site in order for a reaction to take place. Once the products have been released from the active site, the enzyme can be used again. High temperatures and extreme levels in pH can change the shape of the active site so that the substrate (key) can no longer fit and so the substrate can not be broken down/ joined together - this is the process of denaturing.