Leucine, an essential branched-chain amino acid, plays a vital role in muscle protein synthesis and metabolic regulation. However, its derivative, PTH-Leucine, with the CAS number 4399-40-0, has carved out a distinct and critical niche in the realm of analytical chemistry and biochemistry. This article aims to explore the chemical characteristics and the specific applications that make PTH-Leucine an indispensable tool for researchers.

Chemically, PTH-Leucine is known as Phenylthiohydantoin-leucine. Its molecular formula is C13H16N2OS, and it presents as a white to almost white powder. This physical characteristic, combined with its high purity (often exceeding 98% by HPLC), makes it an ideal standard for analytical procedures. The molecule's structure is derived from the reaction of leucine with phenyl isothiocyanate, a key step in the Edman degradation process.

The primary application of PTH-Leucine is as a reference standard in the Edman degradation method for protein sequencing. When a protein or peptide is subjected to this process, the N-terminal amino acid is cleaved and converted into its corresponding PTH derivative. By comparing the resulting derivative with known standards, such as PTH-Leucine, researchers can identify the specific amino acid at that position. This systematic process allows for the determination of the complete amino acid sequence of a protein, which is fundamental for understanding its function, structure, and potential therapeutic uses.

Beyond protein sequencing, PTH-Leucine finds utility in various research settings. It can be used in studies focusing on the metabolism of amino acids or their derivatives, in quality control assays for biochemical products, and as a calibration standard in chromatography. The consistent availability of reliable PTH-Leucine supports reproducibility in laboratory experiments, a cornerstone of scientific progress. The chemical industry, through manufacturers like NINGBO INNO PHARMCHEM CO.,LTD., plays a crucial role in synthesizing and supplying these high-purity compounds, ensuring that the scientific community has access to the tools necessary for cutting-edge research.

In summary, PTH-Leucine (CAS 4399-40-0) is a vital analytical reagent whose specific chemical properties and high purity are leveraged in critical scientific applications, most notably in protein sequencing. Its role highlights the importance of specialized chemical intermediates in advancing fields like proteomics and biochemistry.