For chemists and researchers involved in peptide synthesis, a thorough understanding of the specifications of key reagents is essential for successful experimental design and execution. Fmoc-L-Lys(Dde)-OH, a widely used protected amino acid derivative, boasts several important characteristics that define its utility. This article delves into the key specifications of Fmoc-Lys(Dde)-OH, providing valuable information for those looking to buy or utilize this critical building block.

The chemical name for Fmoc-Lys(Dde)-OH is N-alpha-Fmoc-N-epsilon-[1-(4,4-dimethyl-2,6-dioxocyclohex-1-ylidene)ethyl]-L-lysine. Its CAS number, 150629-67-7, serves as a universal identifier in chemical databases and literature. The molecular formula is C31H36N2O6, and its molecular weight is approximately 532.63 g/mol. These basic identifiers are crucial for accurate referencing and chemical inventory management.

One of the most critical specifications for Fmoc-Lys(Dde)-OH is its purity. Typically, high-quality Fmoc-Lys(Dde)-OH is supplied with a purity of ≥99.0%. This high degree of purity is vital for solid-phase peptide synthesis (SPPS) as it minimizes the occurrence of side reactions and ensures the production of a clean, high-purity final peptide product. Impurities could lead to shortened peptide sequences, deletion sequences, or other undesirable byproducts that complicate purification and reduce yield.

The appearance of Fmoc-Lys(Dde)-OH is also an important physical characteristic. It is commonly described as a white to off-white to pale yellow powder. While slight variations in color can occur due to the manufacturing process or trace impurities, a significant deviation from this description might warrant further investigation into the product's quality.

The primary functional advantage of Fmoc-Lys(Dde)-OH lies in the orthogonal protection strategy it enables. The Dde protecting group on the epsilon-amino group is stable under the basic conditions (e.g., piperidine) used to remove the Fmoc group from the alpha-amino terminus. Conversely, the Dde group can be selectively cleaved using mild nucleophilic reagents such as hydrazine or hydroxylamine. This distinct reactivity allows for site-specific modifications on the lysine side chain during peptide elongation, facilitating complex syntheses such as branched peptides or peptide conjugates. Understanding this chemical property is key for effective custom peptide synthesis.

When considering where to buy Fmoc-Lys(Dde)-OH, it's important to note that the price will vary based on the quantity purchased and the supplier. However, given its role in enabling sophisticated peptide synthesis, it is considered a valuable reagent. Researchers should consult Certificates of Analysis (CoAs) provided by suppliers to verify lot-specific data, including purity assays (often by HPLC) and any relevant physical or spectral data.