 These include HPLC, mass spectrometry, NMR spectroscopy, and X-ray crystallography.Although most applications of protein-directed DCC to date involved the use of single protein in the DCL, it is possible to identify protein ligands by using multiple proteins simultaneously, as long as a suitable analytical technique is available to detect the protein species that interact with the DCL components.This approach may be used to identify specific inhibitors or broad-spectrum enzyme inhibitors.