An enzyme is a protein which accelerates, or (catalyzes), the chemical reactions of living cells. Most biochemical reactions would be too slow to support life without enzymes. Enzymes can be manipulated through the science of enzymatic engineering which alters existing natural substances or builds new ones from natural or artificial materials. Enzyme research and enzymatic engineering include methods and concepts from protein chemistry, molecular biophysics, and molecular biology.

The term enzyme, coined in the late nineteenth century, means leavening and people have recognized the importance of enzyme activity for thousands of years. One of the earliest and most well known of all enzyme-catalyzed reactions is the fermentation of sugar to alcohol. The first enzyme to be isolated was diastase, which catalyzes the hydrolysis of starches into sugars, in 1833. It was also the first enzyme to be patented, in 1894 by Jokichi Takemine (1854-1922). Pepsin, an important enzyme...