Extracellular proteases from Legionella.

Bacterial endopeptidase (proteinase) activity can be specifically registered using synthetic chromogenic peptides. This method does not replace, but adds to the previously existing methods for measuring proteolytic activity. The use of concentrated broth filtrates from Legionella bacteria on a number of different peptides has permitted the establishment of peptide hydrolysis patterns. To some extent these patterns appear species specific. Thus, a close similarity is demonstrated between strains belonging to Legionella pneumophila, as well as a difference between L. pneumophila and other species within the genus Legionella. L. micdadei strain Tatlock does not present extracellular endopeptidase activity. Recently, a number of cell- or cell wall-bound endopeptidases has also been registered. They are found in all Legionella strains hitherto assayed, including the Tatlock strain.