Alpha Assay

Stenroos K, Hurskainen P, Eriksson S et al (1998) Homogeneous time-resolved 1L-2-IL-2R alpha assay using fluorescence resonance energy transfer. Cytokine 10 495 99... 

Commercial name Assay, min % Amine value, mg KOH/g Specific gravity, 20°C/20°C Color, ALPHA, max... 

Gobel, J., Saussy, D. L., and Goetiz, A. S. (1999). Development of scintillation-proximity assays for alpha adrenoceptors. J. Pharmacol. Toxicol. Meth. 42 237. 

Mclssac and Joshl, M. S. "Prenatal Detection of Neural Tube Defects. Comparison Between Alpha Fetoprotein and Beta-Trace Protein Assays". Amer. J. Obstet. Gynecol,... 

DOE. 1995a. Assays and screening of alpha contaminated soils using low-resolution alpha spectroscopy of thick soil samples. Washington, DC U.S. Department of Energy. NTIS/DE95008969. 

Salminen, O., Whiteaker, P., Grady, S.R., Collins, A.C., McIntosh, J.M., Marks, M.J. The subunit composition and pharmacology of alpha-Conotoxin Mil-binding nicotinic acetylcholine receptors studied by a novel membrane-binding assay. Neuropharmacology. 48 696, 2005. 

Amplified Luminescence Proximity Homogeneous Assay (AlphaS-creen ) technology have been reported [50,51]. With an HTS methodology in hand and orthogonal assays previously developed [47-49], nonpeptide antagonists of methyl lysine binding should appear from diversity screening approaches in the near future. 

Payre, N., Cottaz, S. and Driguez, H. (1995). Chemoenzymatic synthesis of a modified pentasaccharide as a specific substrate for a sensitive assay of alpha-amylase by fluorescence quenching. Angew. Chem. Int. Ed. Engl. 34, 1239-1241. 

Dialkyl substitution on the alpha-carbon also abolishes activity, the a,a-dimethyl analog of DOM, Structure 10, is inactive in a variety of assays (10). Linking the two alpha-methyls to give the cyclopropyl analog Structure 11 restores activity in a cat behavioral model (10). The difference in activity between 10 and 11 has been ascribed to the inability of 10 to adopt an antiperiplanar... 

In view of the activity of 13, but the lack of activity for the alpha-ethyl homolog of DOM, the two isomeric ring-methylated derivatives Structures 16a and 16b were recently prepared (114). Neither isomer showed significant activity, either as an agonist in the rat fundus preparation or in a mouse assay, when compared with 13. It would appear that little bulk can be tolerated near the alpha-carbon, other than a methyl or methylene. 

M. A. Chan, A. C. Bellem, and E. P. Diamandis, Time-resolved immunofluorometric assay of alpha-fetoprotein in serum and amniotic fluid with a novel detection system, Clin. Chem. 33, 2000-2003 (1987). 

Braun and Alsenz6 used an ELISA to detect aggregates in interferon-alpha (IFN-a) formulations. They analyzed IFN-a formulations for possible aggregate formation because all marketed interferons are reported to induce antibodies to some extent. Because of its stabilizing effects, human serum albumin (HSA) is used in the formulation of marketed IFN-a at a great excess over IFN-a itself. HSA can also interact with other proteins. Braun and Alsenz developed an ELISA for the detection of both IFN-a-IFN-a and HSA-IFN-a aggregates. A MAb was used for the capture and detection of the IFN-a and a polyclonal for the detection of HSA. The assay is shown schematically in Figure 11.4. 

Braun, A. and J. Alsenz (1997). Development and use of enzyme-linked immunosorbent assays (ELISA) for the detection of protein aggregates in interferon-alpha (IFN-alpha) formulations. Pharm Res 14(10) 1394-1400. 

Von, L.A., Kumpf, R., Menzel, S., Reulle, D., Griebel, R., Valler, M.J., and Buttner, F.H., Miniaturization and validation of a high-throughput serine kinase assay using the alpha screen platform, /. Biomol. Screen., 9, 719, 2004. 

Fig. 2.17 Relative non-covalent binding affinities of a variety of drug candidates to RCS4 and G alpha proteins based on the relative S/N ratios in the CPC spin column/ESI-MS assays to that of 250 pg of the respective compound (normal font) and after normalizing all the values...

Fig. 2.16 GPC spin column binding assay of RGS4 and G alpha proteins with WY817 (MW 450 Da). Positive ion ESI mass spectra for compound WY817, a weak binder to RGS4 protein and non-binder to G alpha protein. A miniature P6 GPC spin column was used. (A) ESI-MS response for 250 pg of reference compound WY817 (no GPC spin column used), (B) ESI-MS response for GPC spin column (P6 gel, 1 cm long, 100 pL volume) eluate when 100 pg of WY817 were passed...

CGTase Activity Assay. Aaivity was measured by the Pharmacia Phadebas Amylase Assay at pH 6.0, 60 C in O.IM sodium acetate (100 ppm Ca+ " ) for 15 minutes using B, stearothermophilus alpha-amylase as a standard. Alpha-amylase preparations were assayed under the same conditions. One Phadebas unit is defined as the amount of enzyme that will catalyze the hydrolysis of 1.0 micromole of glucosidic linkages of Lintner starch per minute at 6OOC, pH 6.0. 

OECD. 2006e. Stably transfected transcriptional activation TA) assay for detecting estrogenic activity of chemicals - The human estrogen receptor alpha mediated reporter gene assay using HeLa-hER-9903 cell line. Version October 2006. Paris OECD, http //www.oecd.org/dataoecd/49/55/37531918.pdf... 

Based on several years of experience and analyses, some exceptions have been introduced. The Na+/K+ ATPase assay is screened at 3 x 10 M because of a low hit rate. The cutoff for IC50 follow-up has been raised to 40% inhibition for CCKb, GABAa, GABAB(ib), Kainate, Glycine (strychnine-insensitive), N (neuronal alpha bungarotoxin insensitive) and PAF assays. 

American Society of Human Genetics, Maternal serum alpha-fetoprotein screening programs and quality control for laboratories performing maternal serum and amniotic fluid alpha-fetoprotein assays Policy statement. Can. Med. Assoc. J. 136(12), 1253-1256 (1987). 

An additional complication and opportunity is provided by the fact that the placement of the methyl group on the alpha-position introduces a chiral carbon. The R- and S-isomers have been compared (see in the Qualitative Comments section) and the S-isomer is clearly three or four times more potent that the R-isomer. These were assayed completely blind, with the code having been broken only after the completion of the study. The dramatic differences in potency let the assignment of the more active isomer be made without hesitation. This S-isomer is the d-or dextrorotary one, and has the absolute configuration of the active member of the isomer... 

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