Microarray-Based Kinase Inhibition Assay by Gold Nanoparticle Probes

We report on the development of a new class of kinase microarray for the detection of kinase inhibition based on marking peptide phosphorylation/biotinylation events by attachment of gold nanoparticles followed by silver deposition for signal enhancement. The α-catalytic subunit of cyclic adenosine 5‘-monophosphate-dependent protein kinase (PKA), and its well-known substrate, kemptide, were used for the purpose of monitoring phosphorylation and inhibition. As expected, highly selective inhibition of PKA is demonstrated with the four inhibitors:  H89, HA1077, mallotoxin, and KN62. Furthermore, an inhibition assay demonstrates the ability to detect kinase inhibition as well as derive IC₅₀ (half-maximal inhibitory concentration) plots.