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in biology, natural and synthetic substances that restrain the activity of enzymes in the living organism as well as in acellular systems; they are differentiated according to their mode of action, specificity, and other properties. Metabolic products may function in the body as natural inhibitors of enzymes. By analogy with technology, such inhibition is called feedback inhibition, since the end product of any biosynthetic process specifically inhibits one of its first stages.

Inhibition is effected either at the genetic level (the inhibitor, in this case called a repressor, retards the biosynthesis of one of the enzymes active at the start of the biosynthetic chain) or the kinetic level (the inhibitor, called a retroinhibitor, lowers the activity of that enzyme). Retroinhibition is a frequent case of so-called allosteric control of enzyme activity.

Inhibitors are widely used to study the mechanisms of the catalytic action of enzymes, to establish the nature of functional groups of proteins, and to elucidate the role of various enzyme processes in metabolism. Inhibitors have great practical significance. Thus, the use of toxic chemicals to control harmful insects and weeds is the result of their ability to inhibit processes vitally important to those organisms. The action of certain pharmacological agents and medicines is also based on the inhibition of enzyme reactions. In a broader sense, the term “inhibitors” is used to designate substances that inhibit any complex biological process (for example, growth inhibitors of plants).


Webb, J. L. Ingibitory fermentov i metabolizma. Moscow, 1966. (Translated from English.)


References in periodicals archive ?
ACE inhibitors target angiotensin converting enzyme (ACE).
Biovitrum AB, Sweden, and Swiss-based Santhera Pharmaceuticals AG have signed a license and collaboration agreement that grants Biovitrum the exclusive worldwide rights to Santhera's DPP-IV inhibitor program to select and develop compounds and sell future drugs for a range of metabolic diseases, including type 2 diabetes, obesity and metabolic syndrome.
released results of a small, 10-day human trial of the maturation inhibitor PA-457, the first time more than a single dose of this compound has been tested in HIV-positive people.
With the introduction of 3 protease inhibitors within a few months of each other, there was tremendous marketing pressure from the 3 companies that manufactured these products, leading to intense debates among the companies involved.
In the report of their findings, which was published in the July 2004 issue of the Annals of Neurology, the authors also raise the possibility that proteasome inhibitors in the environment, whether from bacteria, fungi, plant-based foods, or man-made sources, might play a role in the development of some cases of PD.
There was a period in the mid '90s when protease inhibitors were being developed, and they got through so fast--the first human trials and [Food and Drug Administration] approval were two to three years," says David Gilden, former director of treatment information for the American Foundation for AIDS Research.
The risks of premature and very premature delivery that were associated with the use of regimens containing protease inhibitors were similar to those conferred by use of monotherapy or combination therapy without protease inhibitors.
In part, ACE inhibitors and beta-blockers may be underprescribed because the use of new drug therapies often lags research, notes Lindenfeld.
While phase II trials have compared the drug to placebos, the phase III trials focus on the safety and effectiveness of cox-2 inhibitors compared to NSAIDs.
But the foundation's board decided in March that its AIDS Fund should now focus exclusively on providing protease inhibitors for members who cannot afford the drugs.
The clinical study met its primary endpoint of non-inferiority in viral load reduction in HIV-positive patients receiving 50 mg or 125 mg of GS 9137 once daily, each boosted with 100 mg of ritonavir, in combination with an optimized background antiretroviral regimen compared to a boosted comparator protease inhibitor regimen (p=0.
And the thinking at this time is that tipranavir is NOT suitable for the double-boosted protease inhibitor strategy.

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