Assay of cyclic AMP by an isotope dilution test with binding protein

The radioisotope dilution test for cyclic AMP with binding protein from beef muscle can be described mathematically with the assumption that one molecule of binding protein binds one molecule of cyclic AMP. Formulas for the dose response under saturation and nonsaturation conditions are given. Quasilinear plots are calculated from them even under nonsaturation conditions. Good agreement exists between calculated and measured curves.