enzyme inhibition


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Enzyme inhibition

The prevention of an enzymic process as a result of the interaction of some substance with an enzyme so as to decrease the rate of the enzymic reaction. The substance causing such an effect is termed an inhibitor. Enzyme inhibitors are important as chemotherapeutic agents, as regulators in normal control of enzymic processes in living organisms, and as useful agents in the study of biochemistry. See Antibiotic, Chemotherapy, Enzyme

Inhibitors have been classified as competitive, noncompetitive, and uncompetitive. The effect of a competitive inhibitor is to bind only free enzyme. This can be reversed by sufficiently increased substrate concentrations, so that essentially all of the enzyme is bound into an enzyme-substrate complex. Since both noncompetitive and uncompetitive inhibitors interact with the enzyme-substrate complex, their effects are not nullified by increased concentrations of substrate. An uncompetitive inhibitor exerts less effect (as percent of control) at low than at high substrate concentrations, since less of the enzyme is in the form of the enzyme-substrate complex, with which it interacts. A noncompetitive inhibitor, which reacts with both free enzyme and the enzyme-substrate complex, exerts comparable effects at all substrate concentrations.

McGraw-Hill Concise Encyclopedia of Bioscience. © 2002 by The McGraw-Hill Companies, Inc.

enzyme inhibition

[′en‚zīm ‚in·ə·′bish·ən]
(biochemistry)
Prevention of an enzymic process as a result of the interaction of some substance with the enzyme so as to decrease the rate of reaction.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
References in periodicals archive ?
The enzyme inhibition data was supported by the molecular docking study of the active molecules.
Parveen et al., "Phytochemical analysis and enzyme inhibition assay of Aerva javanica for ulcer," Chemistry Central Journal, vol.
The results for acetylcholinesterase enzyme inhibition by cupuacu seed fat was moderate, as shown in Table 2.
For drumstick leaves, the highest percentage (21.6%) of enzyme inhibition was observed when it was microwaved for 20 minutes.
The uncompetitive enzyme kinetics of DHEA's inhibition of G6PD is extremely rare in nature because it can produce a feedforward effect dramatically potentiating the level of enzyme inhibition [3].
For the enzyme-kinetics analysis, assays were performed at varying concentrations of kynuramine (1.90 [micro]M to 500 [micro]M) for determination of the enzyme inhibition constants (Ki) for inhibition of MAO-A and MAO-B with compound 6.
Saifi, "Mushroom tyrosinase inhibition by two potent uncompetitive inhibitors," Journal of Enzyme Inhibition and Medicinal Chemistry, vol.
The correlation between the degree of enzyme inhibition and the severity of manifestations is pertinent only in the initial stage of acute poisoning, inhibition is greater in repeated exposure.
The controversy with the implications of this assay stems from the fact that small levels of enzyme inhibition may exhibit health benefits especially in specific populations such as postmenopausal women who are diagnosed with early stages of estrogen responsive cancer.
Hydro distilled essential oil from buds of Syzygium aromaticum was investigated for antioxidant and enzyme inhibition activities.
The apparent kinetic parameters for the inhibitory potential ([K.sub.i]) were first estimated by graphical methods, such as Lineweaver-Burk, Dixon and secondary reciprocal plots, and were finally determined by non-linear least squares regression analysis, based on the best enzyme inhibition model [18] using the WinNonlin software.
[1.] Khan AW (2012) Phytochemical analysis and enzyme inhibition assay of Aervajavanica for ulcer.