Enzyme Inhibitor

(redirected from Inhibition constant)
Also found in: Medical.

Enzyme Inhibitor

 

a chemical substance that selectively inhibits the activity of an enzyme or a group of related enzymes. Even in very low concentrations, enzyme inhibitors repress an organism’s vital physiological functions. Many toxic substances, including pesticides, such nerve gases as lewisite, and such respiratory toxins as cyanides and hydrogen sulfide, have a toxic effect owing to the inhibition of enzymes, for example, the enzyme cholinesterase in arthropods.

The study of the effect of enzyme inhibitors on enzymes or groups of enzymes facilitates the search for antidotes or for new pesticides to control harmful insects, mites and ticks, and weeds. The term “enzyme inhibitors” sometimes refers to enzymes in the poisons of snakes, bees, and scorpions that destroy tissues or blood cells in man and animals.

References in periodicals archive ?
Theoretical inhibition constant (Ki) from the docking energy between Ops pesticides and fullerene derivatives.
Relationship between the inhibition constant ([K.sub.i]) and the concentration of inhibitor which causes 50 per cent inhibition ([I.sub.50]) of an enzymatic reaction.
Since the basic idea of the proposed method is that [beta]-lactams could behave as inhibitors of AmpC-type [beta]-lactamases, the strength of such inhibition has been evaluated in terms of inhibition constant ([K.sub.i]) towards AmpC [beta]-lactamase in buffer and CENTA substrate.
In the latter case, however, the inhibition constants are no longer true dissociation constants but rather complex functions of several individual dissociation constants.
officinalis Nauclea officinalis AD Alzheimer's disease ACh acetylcholine ChEIs cholinesterase inhibitors C[H.sub.2][Cl.sub.2] dichloromethane MeOH methanol DEB dichloromethane extract of bark DEL dichloromethane extract of leaves MEL methanol extract of leaves HPLC high performance liquid chromatography PTLC preparative thin layer chromatography TcAChE Torpedo californica acetylcholinesterase hBChE human butyrylcholinesterase LB Lineweaver-Burk [K.sub.i] inhibition constant ARTICLE INFO
Following the inhibition rates of the 23 aqueous extracts of the investigated plants, we have chosen six plants that have a percentage higher than 70% such as Cistus, Equisetum arvense (the grain), Matricaria pubescens, Oudneya africana (the pods), Salvia officinalis, and Thapsia garganica, for a new and a same extraction with distilled water followed by an extraction with methanol to investigate the type of enzyme inhibition and to determine the inhibition constants ([K.sub.i]) for each extract.
Though binding energy, inhibition constant are used as important indicators in molecular docking studies, they cannot offer complete characteristics of the interaction in all the cases, thus the use of dynamic simulation becomes inevitable.
A further interaction study of quinine with clinically important drugs by human liver microsomes: determinations of inhibition constant (Ki) and type of inhibition.
Relationship between the inhibition constant (K) and the concentration of inhibitor which causes 50 per cent inhibition (ISO) of an enzymatic reaction.
The inhibition constant [K.sub.i] (0.6%) showed a competitive inhibition (Figure 6A).
The inhibition constant of OM99-2 is 1.6.times.10.sup.-9 M against recombinant pro-memapsin 2.