Biolabeling with 2,4-dichlorophenoxyacetic acid derivatives: the 2,4-D tag.

Many bioanalytic and diagnostic procedures rely on labels with which the molecule of interest can be tracked in or discriminated from accompanying like substances. Herein, we describe a new labeling and detection system based on derivatives of 2,4-dichlorophenoxyacetic acid(2,4-D) and anti-2,4-D antibodies. The 2,4-D system is highly sensitive with a KD of 7 × 10−11 M for the hapten−antibody pair, can be used on a large variety of biomoleculessuch as proteins, peptides, carbohydrates, and nucleic acids, is not hampered by endogenous backgrounds because 2,4-D is a xenobiotic, and is robust because 2,4-D is a very stable compound that withstands the conditions of most reactions usually performed on biomolecules. With this unique blend of properties, the 2,4-D system compares favorably with its rivals digoxigenin( DIG)/anti- DIGand biotin/(strept) avidinand provides an interesting and powerful tool in biomolecular labeling.