Table 2. Activation of mutant TbPKA holoenzymes by different ligands.

	TbPKA holoenzyme	EC50 (95% Cl)
		Inosine	cIMP	Adenosine	Guanosine	cAMP
WT	RBC-A -GELELMYQTPTVA- RBC-B -GELEFLNNHANVA-	18 (13–22) nM*	- ‡	5 (3-7) µM*	0.14 (0.08–0.19) µM*	- ‡
Mut ¶
	RBC-A -GELALMYQTPRAA- RBC-B -GELAFLNNHARAA-	300 (160–600) µM†	0.34 (0.2–0.7) µM†	- ‡	370 (130–1000) µM†	33 (26–45) µM†
	RBC-A -GELALMYQTPTVA- RBC-B -GELAFLNNHANVA-	28 (23–35) µM†	nd**	nd	nd	- §
3	RBC-A -GELELMYQTPVVA- RBC-B -GELEFLNNHAVVA-	28 (15–37) nM†	nd	nd	nd	nd
4	RBC-A -GELELMYQTPRVA- RBC-B -GELEFLNNHARVA-	36 (29–44) nM†	24 (22–26) µM†	nd	nd	- §
5	RBC-A -GELALMYQTPRVA- RBC-B -GELAFLNNHARVA-	18 (15–20) µM†	0.5 (0.3–0.6) µM†	nd	nd	90 (71–115) µM†
6	RBC-A -GELALMYQTPRAA- RBC-B -GELEFLNNHANVA-	0.2 (0.16–0.25) µM†	14 (10–25) µM†	- ‡	1.2 (0.6–2.6) µM†	25 (19–38) µM†
7	RBC-A -GELELMYQTPTVA- RBC-B -GELAFLNNHARAA-	1.1 (0.9–1.4) µM†	7 (5-11) µM†	21 (13–30) µM†	23 (17–32) µM†	- §

^*mean half activation constants (EC₅₀) and 95% confidence interval (95% Cl) for ≥ 3 biological replicates.

^†mean half activation constants (EC₅₀) and 95% confidence interval (95% Cl) for technical triplicate of a single biological experiments­­.

^‡no activation was detected up to a maximum concentration of 5 mM.

^§no activation was detected up to a maximum concentration of 2 mM.

^¶number given to the respective mutant; site-directed mutations indicated in red.

^**not determined.