Expansion into Tyrosine Kinases

The growing interest in screening kinases has prompted the development of many assay technologies. Cisbios HTRF KinEASE platform developed in partnership with Millipore, uses universal biotinylated substrates with just one monoclonal antibody, labelled with europium cryptate (EuK) for a sensitive, specific detection of the phospho-peptide. Now, the initial assay for screening serine/threonine kinases (STKs) has been extended to include tyrosine kinases (TKs). The KinEASE TK uses a unique substrate containing a single phosphorylation site recognized by a Eu(K) labelled anti phospho-tyrosine antibody. After the kinase reaction, the addition of the antibody and streptavidin XL665 to capture the biotinylated substrate allows FRET to occur. This signal increases proportionally with kinase activity and the amount of the kinase added. Figure 1 shows excellent signal to background ratios obtained with a panel of tyrosine kinases (cytosolic and receptor).