What are Enzymes?
Enzymes are proteins that act as biological catalysts by speeding up chemical reactions. The molecules upon which enzymes may act are called substrates. They are essential for digesting food, helping muscle and nerve function, etc. Enzymes can either be proteins which they usually are, or RNA molecules (also known as ribozymes). Proteins are one of the major biomolecules; the others are carbohydrates, nucleic acids, and lipids.