Cofactorcontaining

Cofactor-containing describes enzymes or proteins that require a non-polypeptide factor to achieve catalytic activity. A cofactor can be a metal ion, a small organic molecule known as a coenzyme, or a prosthetic group that remains tightly attached to the enzyme. When a protein contains its required cofactor, it is often referred to as a holoenzyme; the corresponding apoenzyme is the protein alone without the cofactor.

Cofactors serve a variety of roles in catalysis. Metal ions such as zinc, magnesium, or iron can act as Lewis acids to polarize substrates or stabilize charged intermediates, or participate directly in redox chemistry. Coenzymes are organic molecules that transfer electrons, atoms, or functional groups during a reaction; common examples include NAD+/NADH, FAD, coenzyme A, and biotin. Prosthetic groups are cofactor species that are tightly bound to the enzyme, sometimes covalently, as in the heme group of cytochromes or biotin in carboxylases. Together, cofactors extend the chemical versatility of enzymes beyond what amino acids alone can provide.

The presence of cofactors is essential for many metabolic processes. Some enzymes are metal-dependent metalloenzymes, while others are flavoproteins or pyridine nucleotide-dependent dehydrogenases. Defects in cofactor binding or availability—often related to vitamin deficiencies—can impair enzyme function and lead to metabolic disorders. The term cofactor-containing is therefore a concise way to describe enzymes that rely on these non-protein components for activity and specificity.