J. Ng et al., AMINOPEPTIDASE ACTIVITIES IN PEPTOSTREPTOCOCCUS SPP. ARE STATISTICALLY CORRELATED TO GELATIN HYDROLYSIS, Canadian journal of microbiology, 44(3), 1998, pp. 303-306
One hundred Peptostreptococcus isolates from five species were assesse
d for their ability to hydrolyze gelatin. Most Peptostreptococcus magn
us (95.8%) and Peptostreptococcus micros isolates (79.0%) hydrolyzed g
elatin in contrast to Peptostreptococcus asaccharolyticus (8.0%), Pept
ostreptococcus anaerobius (10.0%), and Peptostreptococcus prevotii iso
lates (16.7%). Gelatin hydrolysis in Peptostreptococcus magnus and Pep
tostreptococcus micros isolates correlated (r = 0.80; P = 0.0019) with
more aminopeptidases produced than Peptostreptococcus asaccharolyticu
s, Peptostreptococcus anaerobius, or Peptostreptococcus prevotii. The
five species were further classified into three groups using the exten
ded Tukey test (P < 0.0001) based on the mean percentage of aminopepti
dases produced by each species with Peptostreptococcus magnus and Pept
ostreptococcus micros belonging to group I, Peptostreptococcus asaccha
rolyticus and Peptostreptococcus prevotii belonging to group II, and P
eptostreptococcus anaerobius forming group III. An analysis of possibl
e proteolytic activity of four selected Peptostreptococcus magnus isol
ates indicated that only 5 of 11 substrates were hydrolyzed as compare
d to a control isolate of Porphyromonas gingivalis W83, which had a st
rong proteolytic profile. Therefore, gelatin hydrolysis by Peptostrept
ococcus spp., in particular Peptostreptococcus magnus and Peptostrepto
coccus micros, is probably due to a variety of aminopeptidases rather
than proteinases.