Inhibition enzymatic activity

The specific therapy consists in concurrent use of two antidotes differing by mechanism of action cholinolytics eliminating anticholinesterase effects on CNS, and cholinesterase reactivators (ChR) ensuring the restoration of inhibited enzymatic activity. 

Cyanide can inhibit enzymatic activity by binding to the metallic cofactor in metalloenzymes. 

The inhibition of metabolic activity by integration of the systems is also seen in enzymatic activity. Ilyin and Titova (1963), working with rats, showed that enzymatic reactions proceeded at higher rates in denervated tissue than in innervated. Many hormones also inhibit enzymatic activity, while others such... 

Several thieno[3,2-d]pyrimidine-2,4-diones 267 were evaluated in vitro for their ability to inhibit enzymatic activity on partially purified bovine lens aldose reductase. A high level of in vitro activity was demonstrated (ICjo 10"6 to 4 x 10 8 M) (91JMC1492 93MI1). 

Competitive Inhibition Enzyme Assays. Estimates of antibody-lysozyme dissociation constants can be obtained by taking advantage of the fact that most monoclonal antibodies efficiently inhibit enzymatic activity.3 5 The combining site of HyHEL-10, which is presented as an example, also has been demonstrated by X-ray crystallography to overlap a portion of the catalytic site of lysozyme.7 A constant concentration of lysozyme is incubated with varying amounts of antibody, and amounts of free (unbound) lysozyme molecules are estimated by the proportion of catalytic activity remaining. The assay assumes that the addition of Micrococcus lysodeikticus cell walls and concurrent dilution of the antibody-antigen mixture do not disturb the equilibrium. 

In reversible inhibition, enzymatic activity is regained by the systemic elimination of inhibitor/ such that the time to enzyme recovery is dependent on the elimination half-life of the inhibitor. Competitive inhibition is characterized by competition between substrate and inhibitor for the enzyme s active site. Competition for enzyme binding can be overcome by increasing the concentration of substrate/ thereby sustaining the... 

DDT and parathion (DDT induces and parathion inhibits enzymatic activity) ... 

Residual water content can also affect solubility specihcally, hydrophobic solvents can enhance water packing into a solvation layer. Hydrophilic solvents solubilize water, pulling it away from the protein surface, thus decreasing the protein hydration (Zaks and Klibanov, 1988a Zaks and Klibanov, 1988b Hailing, 1990 Cowan, 1997). Elimination of the hydration shell can induce denaturation and inhibit enzymatic activity (Schulze and Klibanov, 1991). However, a balance is required since excess water can accelerate chemical degradation. 

ChoUnesterase inhihitors—Class of medication that inhibits enzymatic activity of acetylcholinesterase, butyrylchoUnesterase, or both in order to prevent the degradation of acetylcholine. 

Molina, Y., Vedia, L., McDonald, B., Keep, B., Briine, B., DiSilvio, M., Billiar, T. R., and Lapetina, E. G. (1993). Nitric oxide-induced 5-nitrosylation of glyceraldehyde-3-phosphate dehydrogenase inhibits enzymatic activity and increases endogenous ADP-ribosylation. J. Biol. Chetn. 267, 24929-24932. 

Studies conducted on the inhibition of libonucleoside diphosphate reductase by the preformed iron chelate of 1-formylisoquinoline thiosemicarbazone (1) [(Fe)IQ-11 have shown that under appropriate conditions (Fe)IQ-1 was essentially equal to (1) as an inhibitor of enzymatic activity (78). At a concentration of (Fe)IQ-l which inhibited enzymatic activity by 73% in the absence of added Fe, only 30% inhibition was observed when Fe " was added to the preparation. In contrast, (1) decreased enzyme activity 65% in the presence of Fe but only 15% without Fe. The findings imply that Fe(IQ-l) is the active form of the inhibitor and stress further complexities in the mode of inhibition. 

Flavonoids inhibit enzymatic activities associated with plasma membrane and involved in lipid peroxidation. In plants and animals, major flavonoids such as quercetin inhibit... 

For preservation of food it is mandatory to inhibit enzymatic activity completely if the storage temperature is below the phase transition temperature Tg or Tg (cf. 0.3.3). With help of a model system containing glucose oxidase, glucose and water as well as sucrose and maltodextrin (10 DE) for adjustment of Tg values in the range of — 9.5 to — 32 °C, it was found that glucose was enzymatically oxidized only in such samples that were stored for two months above the Tg value and not in those kept at storage temperatures below T ... 

Tannins can also affect the nitrogen and carbon cycles they can complex proteins or metallic ions and can present toxicity for microorganisms and inhibit enzymatic activities. In the majority of studies, mineralization of the nitrogen is decreased by the addition of tannins, while the effects on carbon mineralization remain more variable. By their characteristic link to proteins, tannins inhibit the microbial extracellular enz5mies and can also limit the available substrates for microbial growth. The difference in tannin content of the leaves seems to act on the aquatic macroinvertebrate communities using... 

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