Substrate specificity screening of oat (Avena sativa) seeds aminopeptidase demonstrate unusually broad tolerance in S1 pocket

Aminopeptidases are proteolytic enzymes that remove one amino acid at a time from N-terminus of peptidic substrates. In plants, inhibitors of aminopeptidases can find potential applications in agriculture as herbicides. In this report we have used a library of fluorogenic derivatives of natural and unnatural amino acids for substrate specificity profiling of oat (Avena sativa) aminopeptidase. Interestingly, we have found that this enzyme recognizes effectively among the natural amino acids basic residues like Arg and Lys, hydrophobic Phe, Leu and Met, but also to some extent acidic residues Asp and Glu. In the case of unnatural amino acids hydrophobic residues (hPhe and hCha) and basic hArg were preferentially recognized.

► Oat (Avena sativa) aminopeptidase has a very broad substrate specificity.
► Arg and Lys are the preferred natural amino acids in S1 pocket.
► Large hydrophobic unnatural amino acids are the most preferred by oat AMP.
► Oat (A. sativa) AMP tolerate basic, acidic and neutral amino acids in S1 pocket.