Enzymes are proteins that have catalytic functions indispensable to maintenance and activity of life. All chemical reactions occurring in a living organism are dependent on the catalytic actions of enzymes, and this is why enzymes are called Biotransformation. At present, there are about 4,000 kinds of enzymes whose actions are well known.
Enzymes function in a mild environment similar to the body environment of a living organism, and they support life by synthesizing and degrading materials that constitute the building blocks of the organism and by creating energy. Enzymes function as highly selective catalysis in such a way that they selectivity catalyze specific reactions (reaction specificity) and specific materials (substrate specificity).
Technology for utilizing enzymes for the improvement of our life is a key feature of biotechnology.
Humankind has been concerned with enzymes from ancient times when enzymes were unknown; humankind unknowingly used microbial fermentation techniques in food processing. In ancient Egypt, they produced breads or beer by fermentation. In Japan too, we have a long history of producing sake by fermentation even from the Jomon period. It is only in the nineteenth century that fermentation was unmasked. Now we know that enzymes are the true entity of fermentation. The word "Enzyme" is derived from the Greek, en (in) +zyme (ferment).
Enzymes are classified into six categories based on the types of reaction catalyzed, that is, oxidoreductase, transferase, hydrolase, lyase, ligase, and isomerase, according to the Enzyme Commission, International Union of Biochemistry and Molecular Biology.
Individual enzymes are further classified systematically based on the chemical name of the substance modified by the enzyme (substrate) and its reaction mechanism. Enzymes are named with the use of letters and numbers: EC plus four numbers representing four elements. For example, 1,4-α-D-Glucan glucanohydrolase (common name: α-amylase) is named as EC 3.2.1.1.
