Receptor assay

Enzyme assays—both kinetic and end-point radiocoordination of proteins, lipid assays, receptor binding assays and tissue-culture techniques... 

Competitive binding immunoassay (e.g., RIA) Enzyme-linked immunosorbent assay (ELISA) Immunoradiometric assay (IRMA) — dual monoclonal antibody assay Receptor binding assay Cell binding assay... 

Increased emphasis on receptor assays -Receptor mimics PURITY ASSAYS... 

The day before the assay, receptor transfectants should be split back to exponential phase growth, 0.25-0.5 x 105 cells per mL, in appropriate cell culture media such as RPMI-1640 plus 10% FCS. 

In vitro functional assays—receptor binding enzyme inhibition/induction... 

The binding site for the iononic cycle presents for the ICTH-assay receptor a more spatially extended attractive region in comparison with the lODC-assay receptor, where the steric strain is less severe. 

The retinoids are more sterically constrained by the lODC-assay receptor than by the ICTH-assay receptor. 

Interestingly, the inhibition curves for all ionenes are much steeper than those for hexamethonium or decamethonium and resemble that for aBgt. The slope of the inhibition curve for aBgt is a consequence of the irreversible binding between receptor and toxin, i.e., free receptor is poisoned gradually by addition of toxin, until at 3 X 10 M aBgt the binding sites are saturated and no active receptor is left that could react with the radioactive toxin added in the assay. Receptor in equilibrium... 

James and co-workers have also used alizarin red S in the design of a D-glucose selective fluorescent assay. Receptor 82 was based on the successful fluorescent PET sensor 27d [154]. Sensor 82 and alizarin red S show a six-fold enhancement over PBA for D-glucose. Sensor 82 can also be used at a concentration ten times lower than PBA. Xjpp for 82 were 140 M" for D-fructose and 66 for D-glucose in 52.1 wt% methanol-water at pH 8.21 (phosphate buffer). 

There should be specific, saturable binding to the receptor, accompanied by pharmacological characteristics appropriate to the functional effects, demonstrable using a radioactive, eg, tritium or iodine-125, ligand to label the receptor. Radioligand binding assays (1,6) have become a significant means by which to identify and characterize receptors and enzymes (see Immunoassays Radioactive tracers). Isolation of the receptor or expression of the receptor in another cell, eg, an oocyte can be used to confirm the existence of a discrete entity. 

Other specific discovery assays have been used such as differential inhibition of a vancomycin resistant S. aureus strain and its susceptible parent, and an assay based on antagonism of the antibacterial activity by N,A/-diacetyl-L-Lys-D-Ala-D-Ala [24570-39-6] a tripeptide analogue of the dalbaheptides receptor. AppHcation of this latter test to 1936 cultures (90) led to the isolation of 42 dalbaheptides, six of which, including kibdelin (Table 3), parvodicin (Table 3), and actinoidin A2 (68) were novel. A colorimetric assay based on competition between horseradish peroxidase bound teicoplanin and the... 

Finally, some amphiphilic sweeteners, eg, aspartame, saccharin, and neohesperidin dihydrochalcone, have been shown to be capable of stimulating a purified G-protein direcdy in an in vitro assay (136). This suggests some sweeteners may be able to cross the plasma membrane and stimulate the G-protein without first binding to a receptor. This type of action could explain the relatively longer response times and the lingering of taste associated with many high potency sweeteners. 

It is not certain that all the effects of DES can be ascribed to its oestrogenic activity (that is to say, directly related to its ability to bind to the oestrogen receptor), but it would appear from experience with this compound that rodent assays are able to detect the relevant toxicological effects. What then was the... 

Oestrogen receptor binding/Reporter gene assay. 

In assay sytems, many of these phytoestrogens are able to bind more avidly to the estrogen receptor than estrogen itself. Why plant products should possess such avid estrogenic compounds is unclear, but it has been suggested that consumption of phytoestrogens by insects may result in alterations in the sex... 

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