Why is competitive inhibition reversible? My Biochemistry book mentions that 'competitive inhibition' is a reversible form of inhibition. But given that the inhibitor is blocking the active site and prevents an enzyme-substrate complex to be formed, how can it be reversible?

A **competitive inhibitor** typically competes for the active site with the substrate). In this textbook case, binding of a competitive inhibitor is reversible), because it binds to the active site of the enzyme, but is also released, making way for the substrate) to bind. The affinity of the substrate), as well as its concentration determine the amount of inhibition (Berg _et al_., 2002).

An irreversible inhibitor may covalently bind to the active site, permanently disabling the enzyme (McDonald _et al_., 2012).

**References**
**-** McDonald _et al_., _Enzymes: Irreversible Inhibition_. In: eLS. John Wiley & Sons Ltd, Chichester (2012)
**-** Berg _et al_., _Biochemistry_. 5th ed. New York: W H Freeman; (2002)