Aminopeptidases (EC 3.4.11) are proteolytic enzymes, which hydrolyze one amino acid from N-terminus
of peptidic substrates. Inhibitors of plant aminopeptidases can find an application in agriculture as
herbicides. Isolation and partial characterization of aminopeptidase from barley (Hordeum vulgare L.)
seeds has been described. The enzyme was purified to molecular homogeneity using a six-step purifi-
cation procedure (precipitation with (NH4)2SO4, followed by chromatography on Sephadex G-25,
DEAE-Sepharose, Sephacryl HR 300, Macro-Prep Q and Phenyl-Sepharose HP columns). The enzyme was
purified 365-fold with recovery above 18%. The molecular weight of the purified enzyme was determined
by SDS-PAGE and gel filtration as 58 kDa, and was found to be a monomer. Its pH and temperature
optima were 7.5 and 52 C, respectively. The enzyme behaves as standard leucine aminopeptidase by
preferring bulky amino acids at the N-terminus, with phenylalanine being of choice