Proto-oncogene tyrosine-protein kinase YES1 has been implicated in regulation of cell growth and survival, apoptosis, cell-cell adhesion, and differentiation. It has been identified as a potential target in basal-like breast cancers. The YES1 Assay Kit is designed to measure YES1 activity for screening and profiling applications using Kinase-Glo® MAX as a detection reagent. The YES1 Assay Kit comes in a convenient 96-well format, with enough purified recombinant YES1 enzyme, Protein Tyrosine Kinase Substrate (Poly-Glu,Tyr 4:1), ATP, and kinase assay buffer for 100 enzyme reactions.