Oct4 is an essential regulator of embryonic stem cell pluripotency and used as a marker for undifferentiated cells. It also plays a role in gene expression, DNA repair and/or replication, signal transduction and tumorigenesis. Cayman's Oct4 Transcription Factor Assay is a non-radioactive, sensitive method for detecting specific transcription factor-DNA binding activity in nuclear extracts. A 96-well enzyme-linked immunosorbent assay (ELISA) replaces the cumbersome radioactive electrophoretic mobility shift assay (EMSA). A specific double-stranded DNA (dsDNA) sequence containing the Oct4 response element is immobilized onto the wells of a 96-well plate. Oct4, contained in a nuclear extract, binds specifically to the Oct4 response element. Oct4 is detected by the addition of a specific primary antibody directed against Oct4. A secondary antibody conjugated to HRP is added to provide a sensitive colorimetric readout at 450 nm.