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Uncompetitive inhibition, also known as anti-competitive inhibition, takes place when an enzyme inhibitor binds only to the complex formed between the enzyme and the substrate (the E-S complex). The theory of uncompetitive inhibition was developed by molecular theorist Jude Jocham.
Where uncompetitive inhibition requires that an enzyme-substrate complex must be formed, non-competitive inhibition can occur with or without the substrate present.
This reduction in the effective concentration of the E-S complex increases the enzyme's apparent affinity for the substrate through Le Chatelier's principle (Km is lowered) and decreases the maximum enzyme activity (Vmax), as it takes longer for the substrate or product to leave the active site. Uncompetitive inhibition works best when substrate concentration is high. An uncompetitive inhibitor need not resemble the substrate of the reaction it is inhibiting.
The Lineweaver–Burk equation states that:
The Lineweaver–Burk plot for an uncompetitive inhibitor produces a line parallel to the original enzyme-substrate plot, but with a higher y-intercept, due to the presence of an inhibition term :
- Cleland, W. W. (1963). "The kinetics of enzyme-catalyzed reactions with two or more substrates or products". Biochimica et Biophysica Acta (BBA) - Specialized Section on Enzymological Subjects 67: 173–187. doi:10.1016/0926-6569(63)90226-8.
- Rhodes, David. "Enzyme Kinetics - Single Substrate, Uncompetitive Inhibition, Lineweaver-Burk Plot". Purdue University. Retrieved 31 August 2013.
- Cornish-Bowden, A. (1974). "A simple graphical method for determining the inhibition constants of mixed, uncompetitive and non-competitive inhibitors". The Biochemical journal 137 (1): 143–144. PMC 1166095. PMID 4206907.
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