AAT Bioquest

What is the difference between enzymes and coenzymes?

Posted July 22, 2020


An enzyme is a protein that acts as a catalyst to increase the biochemical reaction rate without altering itself in the process, while a coenzyme is an organic non-protein molecule that is required by an enzyme to perform its catalytic activity. Therefore, these two types of molecules differ in quite a few aspects:

  • Size: Enzymes are large molecules, while coenzymes are usually small molecules.
  • Nature: Enzymes are mainly globular proteins, whereas coenzymes are non-protein molecules.
  • Function: Enzymes are biological catalysts; while coenzymes are helper molecules to the enzymes, which is necessary for the enzyme to execute its catalytic activity.
  • Change of structure: Enzymes’ structure remains unaltered throughout the reaction, whereas coenzymes are chemically changed after the enzymatic reaction.
Additional resources

Amplite™ Fluorimetric Glucose-6-Phosphate Dehydrogenase (G6PD) Assay Kit

Amplite™ Fluorimetric Coenzyme A Quantitation Kit *Green Fluorescence*

Lodish, H., Berk, A., Kaiser, C. A., Krieger, M., Scott, M. P., Bretscher, A., ... & Matsudaira, P. (2008). Molecular cell biology. Macmillan.

Berg, J. M., Tymoczko, J. L., & Stryer, L. (2008). Biochemistry (Loose-Leaf). Macmillan.