scholarly journals Improvement on the competitive binding assay for the measurement of cyclic AMP by using ammonium sulphate precipitation

1987 ◽  
Vol 245 (3) ◽  
pp. 923-924 ◽  
Author(s):  
T A Santa-Coloma ◽  
M A Bley ◽  
E H Charreau
Keyword(s):  
Cyclic Amp ◽  
Protein Binding ◽  
Ammonium Sulphate ◽  
Cyclic Nucleotide ◽  
Half Life ◽  
Binding Assay ◽  
Great Stability ◽  
Competitive Binding Assay ◽  
Ammonium Sulphate Precipitation ◽  
Protein Binding Assay

The protein-binding assay developed by Brown, Albano, Ekins, Sgherzi & Tampion [(1971) Biochem. J. 121, 561-562] and Brown, Ekins & Albano [(1972) Adv. Cyclic Nucleotide Res. 2, 25-40] was modified by using precipitation with (NH4)2SO4 of the protein-cyclic AMP complex instead of adsorption of the free nucleotide on charcoal. The half-life of the protein-cyclic AMP complex obtained in the presence of charcoal was lower than that of the (NH4)2SO4-precipitated complex. In consequence, owing to the great stability of the precipitated protein-cyclic AMP complex, this method allows more accurate and reproducible determinations.

An improved protein binding assay for cyclic AMP

1974 ◽  
Vol 58 (2) ◽  
pp. 459-468 ◽  
Author(s):  
Charles O. Brostrom ◽  
Christine Kon
Keyword(s):  
Cyclic Amp ◽  
Protein Binding ◽  
Binding Assay ◽  
Protein Binding Assay

USE OF A COMPETITIVE PROTEIN-BINDING ASSAY FOR ADENOSINE 3′:5′-PHOSPHATE FOR THE STUDY OF BOVINE CORPUS LUTEUM ADENYLATE CYCLASE

1977 ◽  
Vol 73 (1) ◽  
pp. 123-134 ◽  
Author(s):  
J. L. YOUNG ◽  
D. A. STANSFIELD
Keyword(s):  
Cyclic Amp ◽  
Adenylate Cyclase ◽  
Protein Binding ◽  
Corpus Luteum ◽  
Binding Assay ◽  
Degradation Products ◽  
Bovine Corpus Luteum ◽  
Protein Binding Assay ◽  
Competitive Protein Binding Assay ◽  
Competitive Protein Binding

SUMMARY The use of a competitive protein-binding assay for cyclic AMP, utilizing the binding protein purified from bovine adrenal cortex, for the study of adenylate cyclase activity of the washed 600 g sediment of bovine corpus luteum is validated. A specific assay for cyclic AMP could only be achieved by removal of the degradation products of ATP on a precipitate of nascent BaSO4. Simple dilution of the sample before assay was not sufficient to eliminate interference from degradation products of ATP. An observed variability in optimal ATP substrate and tissue concentrations is thought to reflect variability in the enzymic profile of the cyclic corpus luteum. Optima with respect to F−, Mg2+ and pH are more clearly defined and are similar to those reported for adenylate cyclase systems of other tissues.

A Simplified competitive protein-binding assay for 25-hydroxycalciferol

1976 ◽  
Vol 68 (2) ◽  
pp. 99-105 ◽  
Author(s):  
B. Garcia-Pascual ◽  
A. Peytremann ◽  
B. Courvoisier ◽  
D.E.M. Lawson
Keyword(s):  
Protein Binding ◽  
Binding Assay ◽  
Protein Binding Assay ◽  
Competitive Protein Binding Assay ◽  
Competitive Protein Binding

24,25-dihydroxyvitamin D3 in serum: sample purification with Sep-Pak C-18 cartridges and liquid chromatography before protein-binding assay.

1983 ◽  
Vol 29 (10) ◽  
pp. 1806-1807 ◽  
Author(s):  
M L Traba ◽  
M Babé ◽  
C de la Piedra ◽  
A Marín
Keyword(s):  
Liquid Chromatography ◽  
Protein Binding ◽  
Serum Sample ◽  
High Performance ◽  
Binding Assay ◽  
Reversed Phase ◽  
Specific Method ◽  
Dihydroxyvitamin D3 ◽  
Protein Binding Assay ◽  
24,25 Dihydroxyvitamin D3

Abstract We describe a precise, specific method for measuring 24,25-dihydroxyvitamin D3 in human serum. A 2-mL serum sample is extracted with acetonitrile and passed through a Sep-Pak C-18 cartridge. The sample is further purified by "high-performance" liquid chromatography under isocratic conditions on a normal-phase column (Radial-Pak silica-gel cartridge), then subjected to a protein-binding assay. The mean concentration of 24,25-dihydroxyvitamin D3 in serum from 22 normal adults (measured during the spring) was 2.9 micrograms/L (SD 1.9, range 6.3-0.42 microgram/L). The intra-assay CV was 7.7%, the interassay CV 11.2%. Purification of the sample with Sep-Pak C-18 and liquid chromatography on normal plus reversed-phase columns leads to a mean value of 3.4 micrograms/L (SD 1.6 micrograms/L, n = 12), not significantly different from results with our method.

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