What is a cofactor?

A cofactor is defined as an inorganic substance that is essential for enzyme activity and catalysis. These molecules assist enzymes in performing their functions by often binding to the enzyme or the substrate, thereby facilitating the biochemical reactions. Cofactors can be metals such as zinc, magnesium, iron, or manganese. They are vital for the proper functioning of many enzymes, as they help in stabilizing the enzyme or substrate, or in participating in the reaction itself by providing necessary chemical groups.

This definition emphasizes the role of cofactors in enzymatic reactions, differentiating them from organic compounds or vitamins that may have other roles in metabolism or cellular function. Understanding the nature and function of cofactors is crucial when studying enzyme mechanisms and biochemistry, as they are fundamental to many biological processes.