S-(2-Aminoethyl)-L-cysteine hydrochloride is primarily used in biochemical research as a substrate or inhibitor in studies involving enzymes, particularly those related to cysteine metabolism. It is also utilized in the synthesis of peptides and proteins, where it serves as a building block to introduce specific functional groups into the peptide chain. Additionally, this compound finds application in the investigation of cellular processes, such as oxidative stress and detoxification pathways, due to its ability to mimic natural cysteine derivatives. Its role in studying enzyme kinetics and mechanisms further highlights its importance in advancing our understanding of biochemical interactions.