A novel class of L-lysine derivatives as aminopeptidase N (APN) inhibitors was designed and synthesized. Activityevaluation showed that compound C7 (IC(50) = 9.6 +/-1.3 microM) and C20 (IC(50) = 13.6 +/- 1.9 microM) were equivalent to the positive control Bestatin (IC(50) = 11.3 +/- 1.6 microM).