Uncompetitive inhibitor

Uncompetitive inhibitor

Uncompetitive inhibition takes place when an enzyme inhibitor binds only to the complex formed between the enzyme and the substrate (the E-S complex).

Mechanism

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 ("K"m 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.

Equation

1/v=frac{K_m}{V_{max} [S] }+frac{1+ [I] /K_i}{V_{max

The Lineweaver–Burk equation for an uncompetitive inhibitor produces a line parallel to the original enzyme-substrate plot, but with a higher y-intercept (due to the inhibition term [I] /K_i ).


Wikimedia Foundation. 2010.

Игры ⚽ Нужен реферат?

Look at other dictionaries:

  • inhibitor — 1. An agent that restrains or retards physiologic, chemical, or enzymatic action. 2. A nerve, stimulation of which represses activity. SEE ALSO: inhibition. α glucosidase i. an oral agent that aids in th …   Medical dictionary

  • uncompetitive inhibition — inhibition of an enzyme by a substance that binds reversibly to the enzyme substrate complex. The enzyme substrate inhibitor complex cannot yield the normal product until the inhibitor is released …   Medical dictionary

  • Enzyme inhibitor — Enzyme inhibitors are molecules that bind to enzymes and decrease their activity. Since blocking an enzyme s activity can kill a pathogen or correct a metabolic imbalance, many drugs are enzyme inhibitors. They are also used as herbicides and… …   Wikipedia

  • Monoamine oxidase inhibitor — MAOI redirects here. For the Easter Island statues, see Moai. Monoamine oxidase Monoamine oxidase inhibitors (MAOIs) are a class of antidepressant drugs prescribed for the treatment of depression. They are particularly effective in treating… …   Wikipedia

  • Phosphodiesterase inhibitor — A phosphodiesterase inhibitor is a drug that blocks one or more of the five subtypes of the enzyme phosphodiesterase (PDE), therefore preventing the inactivation of the intracellular second messengers cyclic adenosine monophosphate (cAMP) and… …   Wikipedia

  • Dihydrofolate reductase inhibitor — A dihydrofolate reductase inhibitor is a molecule that inhibits the function of dihydrofolate reductase, and is a type of antifolate. Since folate is needed by rapidly dividing cells to make thymine, this effect may be used to therapeutic… …   Wikipedia

  • COX-2 inhibitor — COX 2 selective inhibitor is a form of non steroidal anti inflammatory drug (NSAID) that directly targets COX 2, an enzyme responsible for inflammation and pain. Targeting selectivity for COX 2 reduces the risk of peptic ulceration, and is the… …   Wikipedia

  • Acetylcholinesterase inhibitor — Acetylcholine …   Wikipedia

  • Dihydropteroate synthase inhibitor — A dihydropteroate synthetase inhibitor is a drug that inhibits the action of dihydropteroate synthetase. Most are sulfonamides. Tetrahydrofolate synthesis pathway In bacteria, antibacterial sulfonamides act as competitive inhibitors of the enzyme …   Wikipedia

  • Reverse-transcriptase inhibitor — Reverse transcriptase inhibitors (RTIs) are a class of antiretroviral drug used to treat HIV infection, tumors,[1] and cancer.[2] RTIs inhibit activity of reverse transcriptase, a viral DNA polymerase enzyme that retroviruses need to reproduce.… …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”