D-Alanine is the D-enantiomer of alanine, a non-proteinogenic amino acid primarily utilized in pharmaceutical synthesis and biochemical research. It is a key component in bacterial peptidoglycan, the building block of cell walls, and thus plays a critical role in studies of antibiotic action, particularly beta-lactam antibiotics like penicillin that inhibit its incorporation. In neuroscience research, D-alanine functions as an endogenous co-agonist at NMDA receptors, supporting investigations into synaptic plasticity, learning, memory, and potential treatments for schizophrenia and other neurological disorders. In biotechnology, it serves as a chiral building block for peptide and protein synthesis, enabling the study of enzyme kinetics, protein structures, and stereospecific interactions.