Genetic Characterization of pepP, Which Encodes an Aminopeptidase P Whose Deficiency Does Not Affect Lactococcus lactis Growth in Milk, Unlike Deficiency of the X-Prolyl Dipeptidyl Aminopeptidase

We sequenced the pepP gene of Lactococcus lactis, which encodes an aminopeptidase P (PepP), and demonstrated that the X-prolyl dipeptidyl aminopeptidase PepX plays a more important role than PepP in nitrogen nutrition. PepP shares homology with methionine aminopeptidases and could play a role in the maturation of nascent proteins.