Type Inhibition

Inhibition Type Rate Equation Apparent X, Apparent... 

The four major classes or families of mammalian G proteins (Gj, G, G, and G,2) are based on protein sequence homology. Representative members of each are shown, along with known stimuli, effectors, and well-defined biologic effects. Nine isoforms of adenylyl cyclase have been identified (isoforms l-IX). All isoforms are stimulated by a [Pg.461]

Whether the pharmacodynamic advantages of dutasteride confer clinical advantages over finasteride is unknown. Dutasteride inhibits types I and II 5a-reductase, whereas finasteride inhibits only type II. Dutasteride more quickly and completely suppresses intraprostatic DHT (vs. 80% to 90% for finasteride) and decreases serum DHT by 90% (versus 70%). 

Tadalafil inhibits type 11 phosphodiesterase, which is thought to account for the dose-related back and muscle pain seen in 7% to 30% of patients. 

Kinetic Characteristics of Inhibitors of GAT1- or Neuronal-Mediated GABA Uptake11 Inhibitor Structure K,( iAf) Inhibition type Substrate... 

Most enzyme inhibitors act reversibly—i. e., they do not cause any permanent changes in the enzyme. However, there are also irreversible inhibitors that permanently modify the target enzyme. The mechanism of action of an inhibitor—its inhibition type—can be determined by comparing the kinetics (see p.92) of the inhibited and uninhibited reactions (B). This makes it possible to distinguish competitive inhibitors (left) from noncompetitive inhibitors (right), for example. Allosteric inhibition is particularly important for metabolic regulation (see below). 

Table 3. IC50 values and inhibition type of 2-aryl-2-fluoro and 1-aryl-2-fluorocyclopropylamines for tyramine oxidase [130, 131, 133]... 

Compound Isomer type NH2/F relationship R IC50 (pM) Inhibition type pKa log D ... 

Table 4. IC50 values and inhibition type of 2-fluoro-2-phenylcyclopropylamines for recombinant human liver monoamine oxidases (MAO) A and [134a], Adapted by permission of Elsevier Ltd. Copyright 2004.

Inhibition type Rapidly reversible Slowly reversible Rapidly reversible... 

Serreze, D. V., Osborne, M. A., Chen, Y.-G., Chapman, H. D., Pearson, T., et al. (2006) Partial versus full allogeneic hemopoietic chimerization is a preferential means to inhibit type 1 diabetes as the latter induces generalized immunosuppression. 

Table 8.31 provides the added cost for a gas engine driver. These supplemental equipment items are the starter (electric motor or air piston), air tanks, air filters, cooling water pumps, and local piping. An air-cooled radiator is included in Fig. 8.10, the engine cost curve. The radiator of course requires water circulation pumps. For 500 BHP or less, the assumption is made that cooling water of the recirculated inhibited type is available from outside circulated cooling water plant... 

PGR analog/mimetic (epoprostenol, FR181157) Sildenafil Inhibits platelet aggregation Inhibits type-5 phosphodiesterase and reduces platelet activation... 

The initial rates (v in juM/min) of liver alcohol dehydrogenase-catalyzed ethanal reduction are measured in the presence of pyrazole as an inhibitor at the constant concentration of NADH (0.02 M) and the constant concentration of ethanal (2.0 mM), respectively. Propose respective inhibition types and estimate their inhibition constants. 

In addition to the obvious deactivating role of deiodinases, there has been recent evidence that a relationship exists between regulation of deiodination of thyroid hormones in target cells and the intracellular effects of T4 and T3 on pituitary and hypothalamus function. In the rat pituitary, and probably the human, type-II deiodinase-catalyzed conversion of T4 to T3 is a prerequisite for inhibition of TRH release. rT3, produced from T4 by type-III deiodinase, is a potent inhibitor of type-II deiodinase. In a postulated regulatory circuit, rT3 formed from T4 by type-III deiodinase in surrounding CNS (Central Nervous System) tissue enters the pituitary and inhibits type-II enzyme. The resulting decrease in T3 concentration, in turn, causes an increase in TSH secretion49. 

The inhibition of several cytochrome enzymes has been studied using different MIF-based techniques. One of the experimental factors that has to be considered in the modeling of this property is the type of inhibition. Therefore, it is relevant to study a homologous series of compounds which, hypothetically, has the same inhibition type, or it has to be experimentally checked. 

Inhibits release of histamine from mast cell Selective Hi antagonist Inhibits type I hypersensitivity... 

Inhibits release of histamine from mast cell Selective Hi antagonist Inhibits type I hypersensitivity Antihistamine Decreases chemotaxis and eosinopil activation Antihistamine Decreases chemotaxis and eosinophil activation Inhibits release of histamine from mast cell Selective Hi antagonist Affinity for H2, ai 2, and 5HT2-receptor... 

Chiang TM, Kang AH A synthetic peptide derived fiom the sequence of a type I collagen receptor inhibits type 1 collageiMnediated platelet aggr atioa J Clin Invest 100 2079-2084,1997... 

Yu LP Jr., Smith GN Jr., Hasty KA, Brandt KD. Doxycycline inhibits type XI coUagenolytic activity of extracts from hnman osteoarthritic cartilage and of gelati-nase. J Rhenmatol 1991 18(10) 1450-2. 

Phenelzine (Nardil) and tranylcypromine (Parnate) are the two most common MAOIs. Two newer MAOIs are being studied to evaluate their clinical use both have a reduced risk of hypertensive reaction. Selegiline (Deprenyl) is an MAO-B inhibitor (inhibits type B MAO) that is used in the treatment of Parkinson s disease and may be especially useful for treating depression in patients with Parkinson s. Meclobe-mide, a reversible MAO-A inhibitor, is currently used in Europe and Canada and may soon be available in this country. 

The monoamine-oxidase inhibiting type of antidepressants originated from the unexpected central-stimulating effect observed with the tuberculostatic iso-niazid. In the preclinical study of a series of new anti-infectious sulfanilamides, a convulsive effect was observed. An analysis of this unwanted side-effect showed that the convulsions were due to hypoglycemia induced by the anti-infectious sulfanilamide. This hypoglycemic action was recognized as potentially useful... 

Competitive- and Inhibition-type Immunoassay for Determination of Endosulfan... 

Two different types of immunoassays, a competitive-type and an inhibition-type, were developed and compared for the insecticide, endosulfan. The detection range of both assay types was similar, 3-500 ng/ml for the competitive-type and 5-500 ng/ml for the inhibition-type assay. Metabolites of endosulfan and other insecticidal chloro-hydrocarbons possessing a hexachlorocyclopentene structure exhibited considerable crossreaction in both assays, so these immunoassays could be used for detection of class-specific compounds. The inhibition-type immunoassay showed less susceptibility to interfering factors and, therefore, seemed to be more suitable for environmental analysis. 

Table I. Comparison of Competitive- and Inhibition-Type Immunoassay...

Competitive-type immunoassav Inhibition-type immunoassav... 

Table II shows that all derivatives of endosulfan (except endosulfanlactone in the competitive-type immunoassay) exhibited a significant affinity to the antiserum. However, there were major differences in the amount of crossreaction in the assay types, e.g., endosulfandiol was better recognized in the competitive-type immunoassay than in the inhibition-type assay. A possible reason for these differences may be that in one case the antibodies were immobilized and the binding of these antibodies to the solid phase could have an effect on the avidity.

---