Screening kinase inhibitors with microarray-based Raman spectroscopic assay

In this paper, a microarray-based surface-enhanced Raman spectroscopic (SERS) assay for screening kinase inhibitors was demonstrated by the interactions of two kinases, PKA (the alpha-catalytic subunit of cyclic adenosine 5'-monophosphate (cAMP) dependent protein kinase A) and LCK (leukocyte-specific protein tyrosine kinase) with 80 potent kinase inhibitors from a commercial inhibitor library. In this assay, the phosphorylation/inhibition events are marked by biotinylated anti-phosphoserinene/anti-phosphotyrosine antibodies. Silver deposited gold nanoparticles are employed as active SERS substrates by attaching biotin-conjugated gold nanoparticles to the antibodies through avidin bridges. The avidin conjugated fluorescein is used as SERS probe and corresponding SERS spectra have been collected from different spots on the microarray for addressing the activity of kinase. Among the 80 compounds, we have identified 2 inhibitors for PKA and 9 inhibitors for LCK. In addition, the half maximal inhibitory concentration (i.e., IC50 value) and the inhibiting type (type I) of specific inhibitor have also been determined which agree with literature reported results.