A series of peptides and depsipeptides containing 2-methylcarbazic acid (H-Mec-OH), the 2- aza analogue of alanine, was prepared and tested as inhibitors of pancreatic and human granulocyte elastases. A requirement for a minimum chain length as well as specific amino acid sequence was observed which correlates well with both substrate and inhibitor studies by others in this field. The most active inhibitors have the structure Ac-Ala-Ala-Pro-Mec- ...