Table 1. Activation of PKA Isoforms by cAMP Analogs.

Activation of PKA RI and RII PKA were measured with the LiReC assay. EC₅₀ results are grouped according to substitution type and selectivity. Fold selectivity is calculated based on selectivity based on preference for RIα or RIIβ holoenzymes.

	Compound	RIα EC50(nM)	RIIβ EC50 (nM)	RIIβ/RIα Fold Selectivity
	cAMP	36	18	2.0
	cGMP	15000	5080	3.0
RIα	8-Cl cAMP	58	275	0.2
	8-CPT cAMP	33	149	0.2
	8-PIP cAMP	1020	3950	0.3
	8-HA cAMP	358	1150	0.3
	8-Br cAMP	81	184	0.4
	8-MA cAMP	102	223	0.5
	8-AHA cAMP	116	197	0.6
	Sp cAMP	1590	2270	0.7
RIIβ	HE33	414	45	9.2
	6-MBC cAMP	289	59	4.9
	6-Bnz cAMP	170	35	4.9
	6-Phe cAMP	92	20	4.6
	Sp-5, 6-DCl BIMPS	344	83	4.1
	6-MB cAMP	140	39	3.6
	Sp-8-CPT cAMP	342	96	3.6
	Sp-8-B cAMP	1355	435	3.1
	5,6 DCl BIMPS	270	129	2.1
	Sp-8-PIP cAMP	5048	2959	1.7
	2-OMe cAMP	5666	n.d.	n.d.
	2-AEA cAMP	8739	2652	3.3
	2-Cl cAMP	42	45	0.9