Assays competitive binding

Enzyme Immunosensors. Enzyme immunosensors are enzyme immunoassays coupled with electrochemical sensors. These sensors (qv) require multiple steps for analyte determination, and either sandwich assays or competitive binding assays maybe used. Both of these assays use antibodies for the analyte of interest attached to a membrane on the surface of an electrochemical sensor. In the sandwich assay type, the membrane-bound antibody binds the sample antigen, which in turn binds another antibody that is enzyme-labeled. This immunosensor is then placed in a solution containing the substrate for the labeling enzyme and the rate of product formation is measured electrochemically. The rate of the reaction is proportional to the amount of bound enzyme and thus to the amount of the analyte antigen. The sandwich assay can be used only with antigens capable of binding two different antibodies simultaneously (53). [Pg.103]

The sensitivity of these competitive binding assays for 25-OH-D3 is sufficient for the measurement of the... [Pg.53]

Zettner, A. Principles of Competitive Binding Assays (Saturation Analyses) I Equilibrium Techniques. Clin. [Pg.67]

The development of maraviroc (21), much like other chemokine receptor antagonists, started with a high-throughput screen employing a competition binding assay and led to the hit compound UK-107,543. Chemical optimization of this compound led to the development candidate UK-427,857 during this optimization phase, a parallel characterization of the compounds was performed... [Pg.380]

The discovery process for all of these development candidates was similar. Antagonists exhibiting low nanomolar affinities were discovered through competition binding assays, and the antagonists were able to inhibit receptor func-... [Pg.382]

W. Huang, A. Feltus, A. Witkowski, and S. Daunert, Homogeneous bioluminescence competitive binding assay for folate based on a coupled glucose-6-phosphate dehydrogenase-bacterial luciferase enzyme system. Anal. Chem. 68, 1646-1650 (1996). [Pg.401]

Secondary assays depend on the project. Where the primary screen was a cell-based assay, the secondary assay may be a radioligand competition binding assay. In other cases, such as where the primary screen was a biochemical assay, the secondary assay may be a cellular assay, and may be functional or mechanistic. One of the issues that may arise at this stage is that compounds with reasonable activity in the primary assay may not show activity in the secondary assay. There can be a number of reasons for this, including insufficient potency, inability of the compound to get into cells, or a higher intracellular concentration of the natural ligand (e.g., ATP) if the inhibitor is a competitive inhibitor. It is often necessary at this stage to prepare additional compounds in the series to get compounds of sufficient potency and/or permeability so that cellular activity can be demonstrated. [Pg.403]

MS binding assays are also useful for library screening with subsequent hit identification. The concept is simple. First, a library is searched for active compounds in a competitive binding assay. If the result is positive (which is indicated by an increase of the marker signal), the target bound hit is liberated and identified. [Pg.263]

Irrespective of certain limitations, this method offers the opportunity to efficiently conduct competitive binding assays. [Pg.277]

Competitive binding assays simply done with a native marker and mass spectrometric quantification. Angew. Chem. Int. Ed. 2003, 42, 5235-5237 Angew. Chem. 2003, 115, 5393-5395. [Pg.281]

Goldstein, A., Barrett, R. W Ligand dissociation constants from competition binding assays errors associated with ligand depletion. Mol. Pharmacol. 1987, 13, 603-609. [Pg.281]

As the investigation of the interactions between H DAC inhibitors and the enzymes are an important issue, competition assay systems are helpful implements in facilitating the characterization of inhibitor binding. Such a competition binding assay that has been developed for histone deacetylases is based on fluorescence resonance energy transfer (FRET) between tryptophan residues of the histone deacetylase and a fluorescent HDAC inhibitor [38]. In competition with other... [Pg.105]

MAMILLARY MODEL MEAN TRANSIT TIME COMPARTMENTALIZATION Compartments, drug uptake and release, PHARMACOKINETICS COMPENSATION EFFECT COMPETITION PLOT COMPETITIVE BINDING ASSAY COMPETITIVE INHIBITION Competitive inhibitor,... [Pg.732]

Figure 2. Competitive Binding Assay for CT The mixture of sample solution and P-CT-B (l,(XX)-fold diluted. List Biological Laboratories) was preincubated at room temperature for 30 min, and then added to a GMi-coated microtiter plate (50 ng for each well). CT bound to Gmi was determined spectrophotometrically at 405 nm, after adding a solution of 2,2 -azino-bis-p-ethylbenzothioazoline-6-sulfonic acid) as a substrate. A quantitative analysis of sialic acid using TB A method (25) indicate that sialidase-treatment completely eliminated sialic acids of CMP (6). The degree of hydrolysis with pronase-treat CMP was 71 % (6), which was measured by the TNBS method according to the NOVO (NOVO Industry) manual (26).

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