4-Nitro-L-phenylalanine Monohydrate丨CAS 207591-86-4

4-Nitro-L-phenylalanine monohydrate丨CAS 207591-86-4 is a non-standard, synthetic derivative of the naturally occurring amino acid L-phenylalanine. In this compound, a nitro group (-NO₂) is substituted at the para-position (4-position) of the benzene ring in phenylalanine. The addition of one water molecule in its crystalline structure makes it the monohydrate form.

1. Biochemical Research and Protein Engineering
● Incorporation into Proteins: 4-Nitro-L-phenylalanine monohydrate丨CAS 207591-86-4 is commonly used in site-specific incorporation into proteins via expanded genetic code systems. It allows scientists to explore structure-function relationships in proteins.
● Probing Aromatic Residues: The nitro group is electron-withdrawing, making this analog useful for studying electronic effects on protein folding, stability, and enzyme activity.
● Fluorescence Quenching: Although not strongly fluorescent, the nitro group can act as a quencher, which helps in studying protein-protein interactions or conformational changes.
2. Pharmaceutical Research
● Drug Discovery and Design: This analog is used in peptidomimetic design and structure-activity relationship (SAR) studies. It can enhance binding properties or selectivity due to its altered electronic and steric effects.
● Enzyme Mechanism Studies: As a substrate analog or inhibitor, it helps elucidate mechanisms of enzymes that process aromatic amino acids.
3. Synthetic Biology
● Used in non-natural amino acid incorporation techniques, especially in organisms engineered with orthogonal tRNA/synthetase systems. It serves as a tool for bio-orthogonal labeling or post-translational modification mimicry.
4. Materials Science
● Incorporated into biofunctional polymers or hydrogels to add chemical reactivity or modulate electronic properties of the material due to the nitro group.
● Used in molecular imprinting or peptide-based sensing systems, where it imparts unique binding or redox characteristics.

1. Versatile Tool in Protein Engineering
● Enables precise modulation of aromatic interactions and π-stacking in proteins.
● Supports the study of mutations without altering the overall structure too drastically compared to the parent L-phenylalanine.
2. Enhanced Reactivity
● The nitro group introduces electronic perturbations, making the molecule useful in mimicking or disrupting natural aromatic amino acid behavior for research purposes.
3. Improved Binding and Selectivity in Drug Design
● Acts as a functional handle in medicinal chemistry for optimizing the pharmacokinetics or selectivity of peptide-based drugs or inhibitors.
4. Non-toxic and Stable
● Exhibits good stability under lab conditions and is non-toxic in controlled in vitro environments, which is ideal for biochemistry and molecular biology applications.
5. Labeling and Sensing
● Can be used in bioanalytical methods as a quenching agent or redox-sensitive label, especially when precise control of protein behavior is needed.

Conclusion
4-Nitro-L-phenylalanine monohydrate丨CAS 207591-86-4 is a valuable non-canonical amino acid with broad applications in biochemistry, protein engineering, drug development, and synthetic biology. Its unique chemical properties-particularly the presence of a nitro group-enable researchers to study electron distribution, binding affinities, and functional dynamics of biomolecules with great precision. As tools like site-specific amino acid incorporation continue to evolve, the role of such synthetic amino acid analogs is only expected to grow in importance.