The normal physiological role of the enzyme is unknown, but it is not essential for the viability of yeast cells. Has aminopeptidase activity, shortening substrate peptides sequentially by 1 amino acid. Has bleomycin hydrolase activity, which can protect the cell from the toxic effects of bleomycin. Has homocysteine-thiolactonase activity, protecting the cell against homocysteine toxicity. Acts as a repressor in the GAL4 regulatory system, but this does not require either the peptidase or nucleic acid-binding activities (By similarity). Inactivates bleomycin B2 (a cytotoxic glycometallopeptide) by hydrolysis of a carboxyamide bond of beta-aminoalanine, but also shows general aminopeptidase activity. The specificity varies somewhat with source, but amino acid arylamides of Met, Leu and Ala are preferred. Inhibited by E64, a specific inhibitor of cysteine proteases, N-ethylmaleimide, iodacetamide, and mercury and zinc ions. Homohexamer. Binds to nucleic acids. Binds single-stranded DNA and RNA with higher affinity than double-stranded DNA (By similarity). The N-terminus of isoform Cytoplasmic is blocked. Belongs to the peptidase C1 family.