Aspartyl aminopeptidase (EC ) cleaves only unblocked N-terminal acidic amino-acid residues. To date, it has been found only in mammals. We report here that aspartyl aminopeptidase activity is present in yeast. Yeast aminopeptidase is encoded by an uncharacterized gene in chromo-some VIII ( 1 YHR113W, Saccharomyces Genome Database).