Catalyzes the removal of dipeptides from the N-terminus of oligopeptides. Shows a strict specificity for acidic residues (Asp or Glu) in the P1 position, and has a hydrophobic residue preference at the P2 position. Preferentially cleaves the synthetic substrate Leu-Asp-methylcoumaryl-7-amide (Leu-Asp-MCA) as compared to Leu-Glu-MCA. Is involved in amino acid metabolism and bacterial growth of asaccharolytic P.gingivalis, that utilizes amino acids from extracellular proteinaceous nutrients as energy and carbon sources. Enzyme activity is completely blocked by diisopropyl-fluorophosphates, moderately by phenylmethylsulfonyl fluoride (PMSF) and 4-(2-methyl)benzenesulfonyl fluoride, and slightly by pepstatin in vitro. Optimum pH is 7.0. Homodimer. Is exclusively cell-associated. Cell growth is retarded. Complete loss of hydrolysis for ac-DNLD- and LE-MCA. The efficiency of peptide utilization of proteinaceous nutrients is reduced in mutant cells. Belongs to the peptidase S46 family.