Suc-Tyr-Leu-Phe-pNA is a good substrate for human leukocyte cathepsin G and χ- chymotrypsin but not for human leukocyte elastase (HLE). However, Suc-Tyr-D-Leu-D-Phe- pNA inhibited not only cathepsin G and χ-chymotrypsin but also HLE (K i values, 1.1, 0.94 and 0.16 mM, respectively). The p-nitroanilide (pNA) moiety of Suc-Tyr-Leu-Phe-pNA and Suc-Tyr-D-Leu-D-Phe-pNA was substituted with p-benzoylaniline (BZA), p-acetylaniline ( ...