Co-factor

Some enzymes require "helper-molecules" for catalysis to take place. These helper-molecules are called cofactors. Cofactors are non-protein molecules that bind to the enzyme and contribute to reactions in a number of different ways. Co-factors can either be inorganic ions, such as the Zn²⁺ ions required by ADH, or they can be more complex organic or metalloorganic molecules. If a co-factor is bound tightly (sometimes covalently) to the enzyme, it is termed a prosthetic group [1]. zinc ions required by ADH, or they can be more complex organic or metalloorganic molecules. If a co-factor is bound tightly (sometimes covalently) to the enzyme, it is termed a prosthetic group.

Figure 1: Illustrating the role of a co-factor. This co-factor binds the enzyme and contributes to the reaction, and leaves the enzyme with the product in a changed state. This could, for example, be a changed oxidation state, as is the case for NAD⁺N A D plus , which then needs to be restored elsewhere before the co-factor can assist in another reaction.

References

1. Lehninger, Albert L.; Nelson, David L.; Cox, Michael M. (2008). Principles of Biochemistry (5th ed.). New York, NY: W.H. Freeman and Company. ISBN 978-0-7167-7108-1.

Substrate

Product

Theory overview