A protein functioning as a biochemical catalyst in a living organism.
Enzymes are large molecules tailored to facilitate a given type of reaction.
Usually enzymes are proteins, an important class of biomolecules constructed from amino acids. Enzymes catalyze reactions by speeding up life-sustaining processes that under normal body conditions would be much too slow to be useful. Metabolic enzymes are present in every cell, tissue, and organ in the body, and catalyze the reactions associated with the everyday functioning of living cells. They are responsible for keeping the body s systems in proper balance by controlling virtually every chemical reaction associated with metabolism. Because of this, metabolic enzymes are the very basis of the life process.