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Abstract for SignaTECT® cAMP-Dependent Protein Kinase (PKA)
Assay System
The most common method for assaying PKA activity involves measuring the
transfer of 32P-labeled phosphate to a protein or peptide substrate
that is captured on phosphocellulose filters via weak electrostatic
interactions. However, in the presence of multiple kinases (e.g., in a tissue
extract), the 32P-labeled peptides/proteins bound to the
phosphocellulose filter may reflect kinase activity other than that due to PKA.
To increase the specificity of the PKA assay, Promega's SignaTECT®
cAMP-Dependent Protein Kinase Assay (PKA) Assay System uses biotinylated
Kemptide (LRRASLG), a peptide substrate derived from the in vivo substrate
pyruvate kinase. This substrate is highly specific for PKA. The high affinity of
Kemptide for PKA (Km= 5–10µM) provides sufficient sensitivity to
detect the enzyme at levels typically found within most biological samples. The 32P-labeled,
biotinylated substrate is recovered from the reaction mix with the SAM2®
Biotin Capture Membrane, which is a novel streptavidin matrix.
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