By Liz Veloz – Updated August 30, 2022
“Onion cells” is © kaibara87 (Umberto Salvagnin) on Flickr, licensed under Creative Commons Attribution.
Enzymes are protein catalysts that accelerate biochemical reactions without being consumed. They lower the activation energy, enabling cellular processes to occur at life‑sustaining rates.
When an enzyme binds its substrate(s), it forms a transient enzyme‑substrate complex. This interaction repositions reactants, reduces the energy barrier, and drives the conversion to products.
Most enzymes end with the suffix “‑ase.” For example, phosphatase removes phosphate groups, while protease cleaves proteins.
The International Union of Biochemistry and Molecular Biology (IUBMB) recognizes roughly 300 distinct enzyme classes. These include:
Enzymes unlock the chemical energy stored in molecules. Without them, cells would need to invest enormous amounts of energy just to break bonds, rendering metabolism impractical.
By lowering the activation energy, enzymes ensure that reactions proceed swiftly, allowing organisms to thrive in diverse environments.
