So Cofactors are non protein molecules that basically optimize the activity of our enzyme. And Cofactors can be broken down into two categories. So we have our metal ions, which are basically inorganic cofactors and we have the coenzymes, which are the organic Cofactors. And the coenzymes are usually vitamin derivatives. So we have two main types of coenzymes. So coenzymes can be further subdivided into these two groups.