(S)-(-)-2-Amino-4-pentenoic acid hydrochloride is primarily used in organic synthesis and pharmaceutical research. It serves as a chiral building block for the preparation of various biologically active compounds, including peptides and enzyme inhibitors. Its structure allows for the introduction of functional groups, making it valuable in the development of drugs targeting specific enzymes or receptors. Additionally, it is utilized in the study of amino acid metabolism and as a precursor in the synthesis of modified amino acids for biochemical research. Its chiral nature is particularly useful in asymmetric synthesis, enabling the production of enantiomerically pure compounds.