Enzymes are large biological molecules, generally proteins, which catalyze biochemical reactions, converting the starting `substrate` to a specific `product` under the physiological conditions of the living cell. These remarkable biocatalysts are capable of selectively increasing the rate of a specific chemical reaction by as much as 17 orders of magnitude. By analogy, if the rate of approach of the Asian and North American continental plates (assuming 5 cm per year) were increased by the same rate, it would take much less than one second for Vancouver and Tokyo to come together. Without the ability of enzymes to catalyze the vast array of chemical reactions routinely required by living cells, life as we know it would not be possible.

Enzymes, as nature’s version of nanotechnology, hold great potential for biotechnology and are currently employed in many applications (e.g. pulp and paper, textiles, agri-food, etc). Advantages of enzymes, compared to the traditional chemical methods employed by many industries, include cost savings, increased yield and low environmental impact. This is because enzymes have evolved to function under mild conditions (i.e. inside the cells of our body) and to be very selective, both for the specific substrate and reaction catalyzed. However, while the range of reactions for which enzymes are available is impressive, they are limited to those required by biological organisms. The increasing array of molecular biology tools available has enabled the field of protein engineering to develop in recent years, providing us with the opportunity to expand the range of applications for enzymes by changing their properties, including stability under specific conditions (e.g. temperature, shelf life) and substrate and/or reaction specificity.