competitive inhibition


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Related to competitive inhibition: Uncompetitive inhibition

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 ?
Firstly, the interaction between phenol and chlorophenols (2-cp and 4-cp) could be regarded as competitive inhibition as the models revealed.
In evaluating the results of these studies, it appeared that most of the decrease in P sorption due to OM addition can be accounted for by considering the amount of P mineralised from the added OM, and not through competitive inhibition of P sorption by DOC compounds.
The results of two-tailed t-tests for the kinetics study revealed [V.sub.max] values that were not significantly different (P > 0.05) but [K.sub.m] values for the reactions that were significantly different (P < 0.05) (Figure 5; Table 2).This is indicative of competitive inhibition between sucrose and sucralose for binding to invertase, with sucrose having the higher binding affinity, which is why the inhibitory affect is concentration-based.
This indicated a competitive inhibition in both the initial and the steady-state stages of the inhibited reaction.
In other words, because nondepolarizing agents act by competitive inhibition, their effect is dose related: larger doses overcome the effects of acetylcholine and block more receptors.
You consider the possibility that medical treatment aimed at increasing dopamine in affected areas of the brain may be lowering serotonin by competitive inhibition.
In this case where both phenol and 4-cp share the same key enzymes, competitive inhibition exists and cometabolic transformation of 4-cp is strongly affected by the presence of phenol.
In serious cases, calcium gluconate, which acts as a substrate against competitive inhibition of calcium by the ciguatoxin, is typically recommended.
The inhibition constant [K.sub.i] (0.6%) showed a competitive inhibition (Figure 6A).
However, because 3-DA prevents Hcy production through competitive inhibition of the enzyme S-adenosyl-homocysteine hydrolase (SAHH), 3-DA interferes with popular assays of tHcy that are enzyme-conversion immunoassays based on SAHH (1, 2, 4).
Importantly, prebiotics inhibit pathogenic colonization in the gut by competitive inhibition. Some of the recognized prebiotics are fructo-oligosaccharides, lactulose, and trans-oligosaccharides.

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