Protein engineering: Methodology,applications and status

Developments in recombinant DNA (rDNA) technology have made selective alteration of primary amino acid sequences of proteins possible. Such manipulation using genetic engineering techniques has been referred to as protein engineering. Although this technology has seen only limited application in food research to date, this emerging and rapidly expanding technology offers exciting approaches to protein/enzyme modification studies, and may aid in the development of novel processes and/or more functional and nutritious proteinaceous foods. This review outlines some basic protein engineering methodology and strategies. In addition, examples are provided in which site‐directed mutagenesis has been used advantageously in the specific modification of the enzymes subtilisin, lysozyme and chymosin, and of the casein proteins in milk and the storage proteins of potato tubers. These examples indicate the potential of protein engineering technology in investigations of structure‐function relationships, stability, protein folding and conformation.