In the vast landscape of chemical compounds, each has a unique identifier, and for PTH-Leucine, that identifier is CAS 4399-40-0. This registration number signifies a distinct chemical entity, providing a globally recognized name for a compound that plays a crucial role in specific scientific disciplines. This article focuses on the chemical identity and significance of the compound designated by CAS 4399-40-0.

CAS 4399-40-0 is the identifier for PTH-Leucine, also known by its chemical name Phenylthiohydantoin-leucine. This compound is a derivative of leucine, one of the twenty standard amino acids that make up proteins. The 'PTH' prefix indicates its formation through the reaction with phenyl isothiocyanate, a process central to the Edman degradation method used for determining the sequence of amino acids in peptides and proteins.

The molecular formula of PTH-Leucine is C13H16N2OS, with a molecular weight of approximately 248.34 g/mol. These chemical specifications are fundamental for its identification and use in quantitative analysis. In its pure form, as supplied by chemical manufacturers such as NINGBO INNO PHARMCHEM CO.,LTD., PTH-Leucine typically presents as a white crystalline powder. This physical state and high purity are critical for its application as an analytical standard.

The primary utility of CAS 4399-40-0 lies in its role in protein sequencing. During the Edman degradation, each amino acid removed from the N-terminus of a peptide is converted into a phenylthiohydantoin (PTH) derivative. By analyzing these derivatives using chromatography, and comparing them against known standards like PTH-Leucine, researchers can establish the order of amino acids in a protein chain. This process is fundamental to proteomics, structural biology, and the development of new pharmaceuticals.

Understanding the chemical identity associated with CAS 4399-40-0 is therefore essential for researchers working in these fields. It ensures they are sourcing the correct reagent for their analytical needs and can interpret their experimental results with confidence. The consistent availability of this chemical standard facilitates reproducible research outcomes and advances our understanding of biological molecules.

In summary, CAS 4399-40-0 unequivocally identifies PTH-Leucine, a vital derivative of leucine that serves as a cornerstone in protein sequencing and analytical chemistry, underscoring the importance of precise chemical identification in scientific discovery.