Digoxigenin NHS-ester is widely used in molecular biology for labeling nucleic acids and proteins. It enables the covalent attachment of digoxigenin to primary amines in molecules such as DNA, RNA, or peptides through its reactive NHS-ester group. Once labeled, the digoxigenin tag can be detected with high affinity and specificity using anti-digoxigenin antibodies conjugated to enzymes like alkaline phosphatase or horseradish peroxidase. This system is commonly employed in techniques such as in situ hybridization, Southern and Northern blotting, and ELISA assays. Its non-radioactive nature makes it a safe and reliable alternative for detection and visualization of biomolecules in research and diagnostic applications.