Proteolytic activity of Mycoplasma salivarium and Mycoplasma orale 1

Proteolytic activity was found in whole cells and cultural supernatants of Mycoplasma salivarium (PG20 and B isolates) and Mycoplasma orale 1 (CH 19299 and B isolates). Additionally, the activity was examined in cell membrane soluble fractions of PG20 and CH 19299, and detected in them. The level of the activity appeared higher in M. salivarium than M. orale 1. And some differences were found between these mycoplasmas in the affinity for substrates as a result of examination of the activity in cultural supernatants using horse serum, casein and bovine albumin as substrates. That is, PG20 had a higher affinity for horse serum proteins than casein, while CH 19299 the latter than the former, although the lowest affinity for bovine albumin was common to these two strains.