Involved in the hydrolysis of N-acylated or N-acetylated amino acids (except L-aspartate). an N-acyl-L-amino acid + H2O = a carboxylate + an L-alpha-amino acid an N-acetyl-L-cysteine-S-conjugate + H2O = acetate + an S-substituted L-cysteine Binds 2 Zn(2+) ions per subunit. Homodimer. Expressed in kidney. Belongs to the peptidase M20A family.