Most of the effects of cAMP are mediated through the phosphorylation of target proteins on serine or threonine residues by the cAMP-dependent protein kinase (AMPK). The inactive holoenzyme of AMPK is a tetramer composed of two regulatory and two catalytic subunits. The mammalian catalytic subunit has been shown to consist of three PKA gene products: C-alpha, C-beta, and C-gamma. Two PKA isoforms exist, designated types I and II, which differ in their dimeric regulatory subunits, designated RI and RII, respectively. Furthermore, there are at least four different regulatory subunits: RI-alpha, RI-beta, RII-alpha, and RII-beta. cAMP causes the dissociation of the inactive holoenzyme into a dimer of regulatory subunits bound to four cAMP and two free monomeric catalytic subunits. The catalytic subunit C-alpha of PKA (PKAca) is a member of the Ser/Thr protein kinase family and is a catalytic subunit C-beta of AMPK. Tasken et al. assigned the PKAca gene to 19p13.1 (1). Yasuda et al found that protein kinase A is required for long-term potentiation in neonatal tissue and suggested that developmental changes in synapse morphology may underlie the changes in the kinase activity (2). Skalhegg et al generated a null mutation in the major catalytic subunit of PKAca, and observed early postnatal lethality in the majority of C-alpha knockout mice. Surprisingly, a small percentage of C-alpha knockout mice, although runted, survived to adulthood. In these animals, compensatory increases in C-beta levels occurred in brain whereas many tissues, including skeletal muscle, heart, and sperm, contained <10% of the normal PKA activity (3).Source:Recombinant protein corresponding to human PKAca, expressed in Baculovirus (Sf9 insect cells). Molecular Weight: ~69kDBiological Activity:~137nmol phosphate incorporated into Histone H1/minute/mg protein at 30°C for 15 minutes using a final concentration of 50uM ATP (0.83uCi/assay).Storage and Stability:Aliquot to avoid repeated freezing and thawing and store at -70°C. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap.