P6000L, cAMP-dependent Protein Kinase (PKA), catalytic subunit - 500.000 units

Product Information
The catalytic subunit of cAMP-dependent Protein Kinase (PKA) is a serine/threonine protein kinase, which combines, in the absence of cAMP, with the regulatory subunit to form the inactive PKA holoenzyme. Since this is the free catalytic subunit alone, no cAMP is required for activation.

When purified from mammalian tissue, the PKA catalytic subunit is always phosphorylated at T197, essential for catalysis. Most likely a heterologous kinase is responsible for this in vivo phosphorylation of PKA. Although the fully active PKA expressed in E. coli autophosphorylates on both T197 and S338, this does not reflect the mechanism used in eukaryotic cells.

Product Source
Isolated from a strain of E. coli that carries a clone expressing the murine PKA catalytic subunit (α isoform) under control of a T7 expression system (cDNA kindly provided by Dr. G.S. McKnight).

Recognition Determinant
The recognition motif for phosphorylation by PKA is RRXS/TY, where Y tends to be a hydrophobic residue. A Phe in the nearby sequence tends to be a negative determinant for phosphorylation by PKA. Some variations with regard to spacing and basic residues are permissible.