high - throughput screening of large compound libraries is the method of drug - lead discovery . it is now well accepted that for a functional assay , quality is more important than quantity . a biochemical nmr method originally proposed by percival and withers is extended to the screening of ser / thr kinases . the method requires the presence of a cf 3 moiety on the substrate and utilizes 19 f nmr spectroscopy for the detection of the starting and enzymatically modified substrates . experiments can be performed in real time or in an endpoint assay format using protein and substrate concentrations comparable to the ones used by other hts techniques . application of this technique to the phosphorylation of a substrate by the protein ser / thr kinase akt1 is presented .