Abstract Various N-substituted derivatives of glutamine, asparagine, glutaramic, succinamic and maleamic acids have been synthesized and tested in vitro against Plasmodium falciparum. From these compounds, only the glutamine derivatives (1–3) were found to have low activity. Kinetic evaluation of 1–3 revealed that these compounds also act as competitive inhibitors of γ-glutamyl transpeptidase (EC 2.3. 2.2).