Proteolytic Activities of Mycoplasma Salivarium

¹ Department of Oral Bacteriology, Nagasaki University, School of Dentistry, 7-1 Sakamoto-machi, Nagasaki 852, Japan

Proteolytic activity was demonstrated in ATCC 23064 and oral isolates (more than 100 strains) of Mycoplasma salivarium and was suggested to be due to aminopeptidase, some other metalloproteinases, and serine proteinases. An aminopeptidase and a carboxypeptidase were purified from cell membranes of the organism and characterized. In amino acid specificities, the aminopeptidase was different from aminopeplidase B and leucine aminopeptidase, and the carboxypeptidase from carboxypeptidases B and N. These enzymes are considered to play a role in providing the organism with arginine as a main energy source, eventually facilitating the production of ammonia, and in protecting the organism and the other co-existing pathogens from defense mechanisms of the host by inactivating kallidin, bradykinin, tuftsin, and anaphylatoxins such as C3a and C5a.