| Copper is usually utilized in organisms as a cofactor in enzymes or electron transfer proteins that catalyze redox reactions or oxygen chemistry. |
| The trace element chromium is a cofactor for insulin and is important for glucose tolerance. |
| Thiamine pyrophosphate, the active form of vitamin B-1, is a key cofactor of the essential enzymes involved in carbon metabolism. |
| Biopterin is a vital cofactor in tryptophan hydrolase's conversion of tryptophan to serotonin. |
| Along with changes in eNOS, the enzyme responsible for the production of the eNOS cofactor, tetrahydrobiopterin was also increased. |
| Aequorin, when bound to its cofactor coelenterazine, luminesces in response to calcium binding. |
