Effect of 8-substituted cyclic AMP derivatives on soluble guanylate cyclase activity from human platelets

Inhibitory effect of 8-alkyl cyclic AMP derivatives on the soluble guanylate cyclase activity from human platelets was investigated. Cyclic AMP derivatives with alkyl chains of 6 or less carbons at 8-position of the purine base were not inhibitory, but the derivatives with alkyl chains of 7 or more carbons produced significant inhibition of the soluble guanylate cyclase activity. The extent of inhibitory effect increased when a longer alkyl chain was introduced at the 8-position of cyclic AMP. In contrast, 8-alkyl adenosine derivatives did not inhibit the cyclase activity. These results suggest that the platelet guanylate cyclase has an affinity for cyclic AMP derivatives with hydrophobic property as well as for several guanine nucleotides such as GTP or cyclic GMP.