Fluorescein-12-ddUTP can be used for 3’-end labeling of oligodeoxynucleotides using terminal transferase. It also serves as a substrate for E. coli DNA Polymerase I (holoenzyme and Klenow fragment), T4 and T7 DNA polymerases, Taq DNA polymerase and reverse transcriptase. Oligonucleotide probes labeled with fluorescein-12-ddUTP can be detected by direct fluorescence detection (green fluorescence) or by methods using horseradish peroxidase- or alkaline phosphatase-linked anti-fluorescein antibodies. Alternative name: Fluorescein-12-2',3'-dideoxyuridine-5'-triphosphate. Concentration: 1mM. Purity: ≥93% (HPLC). Formulation: Liquid. Solution in water. Long Term Storage: -20°C. Excitation maximum: 496 nm. Emission maximum: 520 nm.