Figure 4

Determination of the activation constant Kact (cAMP) for Cα2 and myr Cα1 containing PKA type I and II holoenzymes. PKA type I and II holoenzymes were made by mixing recombinant Cα2 and myr Ca1, respectively, with either recombinant RIα (panel A) or RIIβ (panel B) in a molar ratio 1: 1.2 (C: R, see Methods). The holoenzymes were incubated with Kemptide (250 μM) and increasing concentrations of cAMP (0,1 nM- 10 μM) to determine the activation constant (Kact). A Kact (cAMP) for RIα-Cα2 and RIα-myrCα1. B Kact (cAMP) for RIIβ-Cα2 and RIIβ-myrCα1. .