Comprehensive Monograph on L-Lysine (DB00123)

Section 1: Molecular Profile and Physicochemical Characteristics

This section provides a definitive characterization of L-lysine, establishing its fundamental chemical identity, structural properties, and physical characteristics. This foundational knowledge is essential for understanding its complex biological roles, pharmacological activities, and applications in clinical and industrial settings.

1.1 Identification and Nomenclature

L-lysine is a small molecule classified as an essential α-amino acid.[1] Its unambiguous identification is critical for scientific research, regulatory affairs, and commercial use. The molecule is cataloged across numerous international chemical and biological databases under a consistent set of identifiers. The primary and most widely recognized CAS Registry Number for L-lysine is 56-87-1.[2] Its unique DrugBank Accession Number is DB00123, which links it to a wealth of curated pharmacological and biochemical data.[1]

The systematic name for the molecule, according to the International Union of Pure and Applied Chemistry (IUPAC), is (2S)-2,6-diaminohexanoic acid, which precisely describes its structure as a six-carbon hexanoic acid with amino groups at the second (α) and sixth (ε) positions, with the stereochemistry at the α-carbon specified as 'S'.[2] Its molecular formula is consistently reported as $C_6H_{14}N_2O_2$, and its molecular weight is approximately 146.19 g/mol.[2]