Rp-8-CPT-cAMPS is a powerful and competitive antagonist of cAMP-induced activation of cAMP-dependent protein kinase (PKA) I and II. Acting as a potent cAMP analog, Rp-8-CPT-cAMPS exhibits a preference for site A of RI over site A of RII. Additionally, it favors site B of RII over site B of RI. This compound effectively inhibits cAMP-dependent PKA activation and demonstrates selectivity in binding to specific sites within the protein kinase.

Rp-8-CPT-cAMPS (100 μM; 15 min) blocks phosphorylation of VASP by 6-Bnz-cAMP and largely reduces VASP phosphorylation by forskolin and fenoterol[2]. Rp-8-CPT-cAMPS (100 μM; 30 min) reduces GTP-loading of Rap1 by both 8-pCPT-2'-O-Me-cAMP and 6-Bnz-cAMP[2]. Rp-8-CPT-cAMPS (100 μM; 30 min) largely diminishes the augmentation of bradykinin-induced IL-8 release by the PKA activator 6-Bnz-cAMP and the Epac activator 8-pCPT-2'-O-Me-cAMP[2]. Rp-8-CPT-cAMPS (10 μM) inhibits the endothelium-dependent and -independent relaxation which induced by Venom in pre-contracted rat mesenteric artery rings[3].