Protein Engineering - One of the most exciting aspects of recombinant DNA technology is that it permits the design, development and isolation of proteins with improved operating characteristics and even completely novel proteins. The simplest example of protein engineering involves site-directed mutagenesis to alter key residues.

The thermostability of lysozyme was increased 100-fold by the introduction of a disulphide bond. Many human proteins are being tested as potential therapeutic agents and a number of them are already commercially available. Protein engineering now is being used to generate second-generation variants with improved pharmacokinetics, structure, stability and bioavailability.