competitive inhibition

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inhibition

 [in″hĭ-bish´un]
1. arrest or restraint of a process.
2. in psychoanalysis, the conscious or unconscious restraining of an impulse or desire. adj., adj inhib´itory.
competitive inhibition inhibition of enzyme activity by an inhibitor (a substrate analogue) that competes with the substrate for binding sites on the enzymes.
contact inhibition inhibition of cell division and cell motility in normal animal cells when in close contact with each other.
noncompetitive inhibition inhibition of enzyme activity by substances that combine with the enzyme at a site other than that utilized by the substrate.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.

com·pet·i·tive in·hi·bi·tion

blocking of the action of an enzyme by a compound that binds to the free enzyme, preventing the substrate from binding and thus preventing the enzyme from acting on that substrate. The competitive inhibitor is often a substrate analogue and binds at the active site; however, this is not an absolute requirement for competitive inhibition. Saturating concentrations of substrate can remove the inhibition. Compare: isostery.
Farlex Partner Medical Dictionary © Farlex 2012

com·pet·i·tive in·hi·bi·tion

(kŏm-pet'i-tiv in'hi-bish'ŭn)
Blocking of the action of an enzyme by a compound that binds to the free enzyme, preventing the substrate from binding and thus preventing the enzyme from acting on that substrate.
Synonym(s): selective inhibition.
Medical Dictionary for the Health Professions and Nursing © Farlex 2012

competitive inhibition

a form of enzyme control in which an inhibitor molecule very similar in structure to the normal SUBSTRATE of an enzyme becomes reversibly bound to the ACTIVE SITE, thus reducing the quantity of enzyme available. However, if excess substrate is present the inhibitor can be forced out by the substrate molecule which takes its place and the reaction proceeds. Compare NONCOMPETITIVE INHIBITION.
Collins Dictionary of Biology, 3rd ed. © W. G. Hale, V. A. Saunders, J. P. Margham 2005
References in periodicals archive ?
In an attempt to evaluate the pharmacophore model by molecular docking results, the competitive inhibitors in their bioactive conformation (bound to PTP1B) were aligned to the common feature pharmacophore model hypothesis.
In order to understand binding modes between PTP1B and 16 competitive inhibitors, we built a common feature pharmacophore model consisting of five chemical features (RAAHH): two hydrophobic groups H, an aromatic ring R, and two hydrogen bond acceptors A.
In human liver microsomes and specific human CYP2C9 isoforms, PSP acted as a competitive inhibitor on the metabolism of tolbutamide (Yeung and Or 2011).
Dihydrotanshinone was not only a potent competitive inhibitor of human CYP1A2 and CYP2C9, but also a potent noncompetitive inhibitor of human CYP3A4.
In the present study, we compared the inhibitory effect of MA to anaphthoflavone, a known competitive inhibitor of CYP1A2 with an [IC.sub.50] value of 0.01-0.02 [micro]M, on phenacetin O-deethylase activity in HLMs, which also exhibited an [IC.sub.50] value of 0.01 [micro]M in our study (Table 1) (Tassaneeyakul et al.
However similar analysis shows kurarinol 3 to be a competitive inhibitor. Compounds 1 and 2 exhibited potent antibacterial activity with 10 [micro]g/disk against Gram-positive bacteria, whereas kurarinol 3 did not ostend any antibacterial activity.

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