Uncompetitive inhibition

Uncompetitive inhibition (which Laidler and Bunting preferred to call anti-competitive inhibition,[1] but this term has not been widely adopted) is a type of inhibition in which the apparent values of the Michaelis–Menten parameters and are decreased in the same proportion.

It can be recognized by two observations: first, it cannot be reversed by increasing the substrate concentration , and second, linear plots show effects on and , seen, for example, in the Lineweaver–Burk plot as parallel rather than intersecting lines. It is sometimes explained by supposing that the inhibitor can bind to the enzyme-substrate complex but not to the free enzyme. This type of mechanism is rather rare,[2] and in practice uncompetitive inhibition is mainly encountered as a limiting case of inhibition in two-substrate reactions in which one substrate concentration is varied and the other is held constant at a saturating level.[3][4]

  1. ^ Laidler, Keith J.; Bunting, Peter S. (1973). The Chemical Kinetics of Enzyme Action. Clarendon Press, Oxford.
  2. ^ Cornish-Bowden, A. (1986). "Why is uncompetitive inhibition so rare? A possible explanation, with implications for the design of drugs and pesticides". FEBS Lett. 203 (1): 3–6. doi:10.1016/0014-5793(86)81424-7.
  3. ^ Cleland, W. W. "The kinetics of enzyme-catalyzed reactions with two or more substrates or products: II. Inhibition: Nomenclature and theory". Biochim. Biophys. Acta. 67 (2): 173–187. doi:10.1016/0926-6569(63)90226-8.
  4. ^ Cornish-Bowden, Athel (2012). Fundamentals of Enzyme Kinetics (4th ed.). Wiley-Blackwell, Weinheim. pp. 25–75. ISBN 978-3-527-33074-4.