An aminopeptidase P from Lactococcus lactis with original specificity.

An aminopeptidase P (E.C. 3.4.11.9) that cleaves the Arg-1-Pro-2 bond of bradykinin has been isolated for the first time from Lactococcus lactis. The peptidase was purified to homogeneity in a 3-step procedure and characterized. It is a monomeric metalloenzyme with a 43 kDa molecular mass, activated by Mn2+ and inhibited by DTT. It differs from the majority of aminopeptidases P already described by displaying a specificity for X-Pro-Pro N-terminal and probably an extended binding site that could accommodate amino acid residues beyond the P'2 position of the substrate.