Assays using a NIMS chip: loosely bound but highly selective

A fluorous-affinity nanostructure initiator mass spectrometry (NIMS) chip has been developed as an enzyme activity assay. As a proof-of-principle, an assay for detecting cysteine-containing peptide phosphorylation by protein kinase A (PKA) was designed using NIMS technology. The efficacy for an enzyme inhibition assay was characterized by deriving an IC50 value from the ratio of the substrate-to-product mass spectral signal intensities, using known inhibitors of PKA and Abl kinase activity. Lastly, the potential use of a NIMS chip as a multiple screening enzyme inhibition platform was explored.