Catalyzes the removal of dipeptides from the N-terminus of oligopeptides. Most potently cleaves the synthetic substrate Met-Leu-methylcoumaryl-7-amide (Met-Leu-MCA), followed by Leu-Arg-, and to a much lesser extent Lys-Ala-, Leu-Asp-, Leu-Glu-, Leu-Lys, and Val-Arg-MCA, while this enzyme does not hydrolyze Gly-Arg-, Gly-Gly-, Lys-Lys-, or Gly-Pro-MCA. Belongs to the peptidase S46 family.