Cofactor

Definition

A cofactor is a non-protein chemical compound that is required for an enzyme's biological activity. Cofactors can be metal ions or organic molecules, often referred to as coenzymes.

5 Must Know Facts For Your Next Test

1. Cofactors are essential for the catalytic activity of many enzymes.
2. Coenzymes are a type of cofactor that are organic molecules, often derived from vitamins.
3. Metal ions like Mg2+, Fe2+, and Zn2+ can act as cofactors.
4. Cofactors can be tightly or loosely bound to the enzyme.
5. The absence of a necessary cofactor can render an enzyme inactive.

Review Questions

• What is the role of a cofactor in enzymatic reactions?
• Distinguish between a coenzyme and a metal ion cofactor with examples.
• How does the absence of a cofactor affect enzyme function?

Related terms

Apoenzyme: An enzyme without its necessary cofactor.

Holoenzyme: A complete, active enzyme with its bound cofactor.

Metalloenzyme: An enzyme that contains one or more metal ion cofactors.