HTRF KinEASE TK is a universal and sensitive assay for high throughput screening of Tyrosine (Tyr) kinases, major targets in drug discovery and, in particular, in oncology research. It combines a peptide substrate called S4 and a single, proprietary monoclonal antibody with HTRF (homogeneous time resolved fluorescence) technology, a sensitive technology for the detection of molecular interactions of proteins in vitro. It limits assay development time, is easily miniaturized and is flexible, meaning it can be performed under a range of conditions, for instance with low consumption of enzyme or with any ATP concentration.