Amastatin is a slow, tight binding, competitive aminopeptidase (AP) inhibitor, first described as an inhibitor of human serum AP-A (glutamyl AP; IC50 = 0.54 μg/ml) but not of AP-B (arginine AP). It also inhibits AP-N (AP-M, alanyl AP; Ki = 20-200 nM), leucyl-cystinyl AP (Ki = 20-220 nM), and endoplasmic reticulum AP 1 (Ki = 41.8 μM). Amastatin is without effect on trypsin, papain, chymotrypsin, elastase, pepsin, or thermolysin.
