The HTRF KinEASE assay series is a semi-universal biochemical platform to study kinase activity. The TK kit uses a specific substrate compatible with tyrosine kinases - cf. validation data provided on this page..The HTRF KinEASE kit series provides a simple biochemical approach to study kinase activity, screen for inhibitors and characterize them. Three STK and one TK kits offer a semi-universal method for assessing phosphorylation on Serine/Threonine and Tyrosine residues, respectively. The HTRF KinEASE TK assay has been validated on 71 Tyrosine kinases, using a single generic substrate. The assay validation section of this page lists them and provides technical tips for setup..