Protein Kinase Assay on Peptide-Conjugated Gold Nanoparticles by Using Secondary-Ion Mass Spectrometric Imaging

Spot the mass of peptides: A label‐free protein kinase assay that uses secondary‐ion mass spectrometric imaging has been demonstrated with peptide‐conjugated gold nanoparticles (AuNPs). With detection of the mass change of peptide substrates in a kinase reaction, AuNP‐enhanced peptide signals enabled the assaying of both the protein kinase and its inhibition by chemical imaging of peptide substrates on a surface (see picture).