It is the cofactor for the enzyme and does not form a permanent part in the enzyme's structure. Sometimes, they are called cosubstrates and are considered substrates that are loosely bound to the enzyme.

Are cofactors permanently bound?

Cofactors can be divided into two types: inorganic ions and complex organic molecules called coenzymes. ... The first is called a "prosthetic group", which consists of a coenzyme that is tightly or even covalently, and permanently bound to a protein.

Do cofactors bind?

Cofactors are generally either bound tightly to active sites, or may bind loosely with the enzyme. They may also be important for structural integrity, i.e. if they are not present, the enzyme does not fold properly or becomes unstable.