Immunorelatedness of Oligopeptidases from Lactobacillus and Lactococcus and Proline Iminopeptidase from Propionibacterium using Double Immunodiffusion Assay

Double immunodiffusion assay showed that species of lactobacilli produce immunologically unrelated oligopeptidases. Polyclonal antibodies (PAbs) specific for intracellular 70 kDa oligopeptidase type PepO from Lactobacillus curvatus reacted with intracellular protein(s) of cell-free extract (CFE) from Lb. paracasei and Lb. casei but not with intracellular proteins of Lb. plantarum, Lb. pseudoplantarum or Lb. helveticus. PAbs specific for 70 kDa oligopeptidase from Lactococcus lactis did not react with proteins in CFE from lactobacilli but at similar PepO activity reacted, with different affinity, with proteins in CFE of various lactococcal cultures. Antibodies specific for intracellular proline iminopeptidase from Propionibacterium freudenreichii reacted with proteins in the CFE from cultures of other dairy propionibacteria only.