Applications
Site-directed mutagenesis is used to generate mutations that may produce rationally designed protein that has improved or special properties.
Investigative tools - specific mutations in DNA allow the function and properties of a DNA sequence or a protein to be investigated in a rational approach.
Commercial applications - proteins may be engineered to produce proteins that are tailored for a specific application. For example, commonly-used laundry detergents may contain subtilisin whose wild-type form has a methionine that can be oxidized by bleach, inactivating the protein in the process. This methionine may be replaced by alanine, thereby making the protein active in the presence of bleach.
Read more about this topic: Site-directed Mutagenesis