EdU Flow Cytometry Assay Kits (HF594) provides a novel method based on click chemistry specifically CuAAC (copper-catalyzed azide-alkyne cycloaddition) enabling direct measurement of DNA synthesis during the S-phase of the cell cycle The thymidine analog EdU (5-ethynyl-2 -deoxyuridine) can be incorporated directly into DNA strands during DNA synthesis The alkyne group on EdU a biologically inert moiety undergoes highly selective reaction with azide-functionalized dyes via the CuAAC reaction forming a stable 1 2 3-triazole product The EdU Cell Proliferation Kit (TMB) specifically targets proliferating cell DNA by linking EdU with biotin azide followed by incubating with HRP-Streptavidin which binds to biotin The bound HRP then catalyzes a colorimetric reaction with TMB substrate allowing final quantification by spectrophotometric detection This kit is designed for use with cell samples and is not suitable for tissue section analysis