Kofaktoret

Kofaktoret, or cofactors, are non-protein chemical compounds or inorganic ions that are required for the activity of many enzymes. Bound to an apoprotein, these cofactors enable catalysis and stabilize intermediates, turning an inactive protein into a catalytically competent holoenzyme.

Cofaktoret are classified as inorganic cofactors (metal ions such as magnesium, iron, zinc) and organic cofactors. Organic cofactors that are small molecules are often referred to as coenzymes. Many coenzymes are derived from vitamins and are essential for the transfer of chemical groups, electrons, or atoms during reactions.

Metal ions commonly participate in catalysis by stabilizing negative charges, orienting substrates, or participating in redox chemistry. Organic cofaktorer, or coenzymes, participate in diverse functions such as electron transfer (NAD+, FAD), acyl or amino group transfer (CoA, pyridoxal phosphate), and carboxylation or carboxyl transfer (biotin).

Examples include NAD+ and NADP+ as electron carriers; FAD; CoA; biotin; lipoic acid; heme groups; and pyridoxal phosphate. In multi-enzyme complexes, different cofaktorer cooperate with multiple active sites, enabling complex metabolic pathways.

Overview: Kofaktoret availability depends on diet and metabolism; deficiencies or imbalances can impair enzyme activity and lead to metabolic disorders. Understanding kofaktorer is fundamental in biochemistry, physiology, pharmacology, and medicine.