ABSTRACT
Enzymes are biomolecules (i.e. produced by living cells) which accelerate chemical reactions. They are thus often referred to as ‘biological catalysts’. Enzymes are mentioned in the introductory section on chemical reactions (10.2.1), but their central role in life processes justifies some further comments. Like catalysts generally, enzymes are not consumed during the reactions they catalyse, and hence can be used over and over again. Unlike inorganic catalysts, however, enzymes are substrate specific. In effect, each enzyme acts upon only one substance (the substrate) or just a few very similar substances.
