Dihydrodipicolinate synthase (DHDPS) is a key enzyme in lysine biosynthesis and an important antibiotic target. The specificity of a range of heterocyclic product analogues against DHDPS from three pathogenic species, Bacillus anthracis, Mycobacterium tuberculosis and methicillin-resistant Staphylococcus aureus, and the evolutionarily related N-acetylneuraminate lyase, has been determined. The results suggest that the development of species-specific inhibitors of DHDPS as potential antibacterials is achievable.