1-Fluoro-2,4-dinitrobenzene

1-Fluoro-2,4-dinitrobenzene (FDNB), also known as Sanger's reagent, is a chemical compound used in biochemistry and organic chemistry for the modification of amino acids and the sequencing of proteins. Its chemical formula is C₆H₃FN₂O₅. FDNB reacts with the amino groups in amino acids and proteins, forming a stable derivative that can be identified and quantified, making it a valuable tool for analyzing protein structures.

Properties

1-Fluoro-2,4-dinitrobenzene is a yellow crystalline solid with a melting point of 21-23 °C. It is soluble in organic solvents such as ethanol, acetone, and benzene but is less soluble in water. The presence of the fluoro and nitro groups on the benzene ring makes FDNB highly reactive towards nucleophiles, such as the amino groups in amino acids.

Synthesis

FDNB can be synthesized by the nitration of fluorobenzene with a mixture of concentrated nitric acid and sulfuric acid, followed by separation and purification steps to isolate the 1-fluoro-2,4-dinitrobenzene isomer from other nitration products.

Applications

Protein Sequencing

The primary application of 1-Fluoro-2,4-dinitrobenzene is in the Sanger's method of protein sequencing. FDNB reacts with the free amino group of the N-terminal amino acid of a protein, forming a dinitrophenyl (DNP) derivative. The protein is then hydrolyzed into its constituent amino acids, which can be separated and the N-terminal amino acid identified by its DNP derivative. This method was a significant advancement in biochemistry, allowing scientists to determine the amino acid sequences of proteins.

Amino Acid Modification

Apart from protein sequencing, FDNB is also used for the selective modification of amino acids. It reacts with the amino groups in amino acids to form dinitrophenyl-amino acids, which can be used in various biochemical studies to investigate the role of specific amino acids in proteins and enzymes.

Safety

1-Fluoro-2,4-dinitrobenzene is considered hazardous. It is a potent irritant to the skin, eyes, and respiratory system. It may also pose risks of long-term health effects, such as cancer, due to its potential to modify DNA. Handling of FDNB should be done with appropriate safety precautions, including the use of personal protective equipment (PPE) and working in a well-ventilated area or fume hood.

External Links

• PubChem Compound Summary for 1-Fluoro-2,4-dinitrobenzene