Cofactors are inorganic molecules that help enzymes carry out their functions as catalysts.In multi-step biological pathways, the cofactors may transfer atoms or groups of atoms from one reaction to another or form part of the active site of the enzyme.Examples of inorganic cofactors are iron, calcium, chloride, magnesium, manganese, cobalt, copper, molybdenum and zinc.Cofactors work by binding to the enzyme.
| Ion | Enzymes |
| Copper | Cytochrome oxidase |
| Iron | Catalase Cytochrome Nitrogenase Hydrogenase |
| Magnesium | Glucose 6-phosphatase Hexokinase DNA polymerase |
| Manganese | Arginase |
| Molybdenum | Nitrate reductase Nitrogenase Xanthine oxidase |
| Nickel | Urease |
| Zinc | Alcohol dehydrogenase Carbonic anhydrase DNA polymerase |