The binding of cyclic nucleotide analogs to a purified cyclic GMP-stimulated phosphodiesterase from bovine adrenal tissue.

The specificity of binding of [3H]cGMP to purified bovine adrenal cGMP-stimulated phosphodiesterase was investigated by adding increasing concentrations of unlabelled analogs of cAMP and cGMP. The data show a perfect correlation between the potencies of stimulation of cAMP phosphodiesterase activity and displacement curves of [3H]cGMP binding. Since the Sp and Rp diastereomers of adenosine 3',5'-monophosphate behaved as a cAMP-dependent protein kinase agonist and antagonist, respectively, the possible biological activity of these compounds and the corresponding cGMP analogs (cGMPS Sp and Rp) on the cGMP-stimulated phosphodiesterase was investigated. The data show no regioselectivity in binding nor on activation of one of the two (Sp) or (Rp) isomers.