Ca. Studdert et al., DETECTION AND PRELIMINARY CHARACTERIZATION OF EXTRACELLULAR PROTEOLYTIC ACTIVITIES OF THE HALOALKALIPHILIC ARCHAEON NATRONOCOCCUS-OCCULTUS, Archives of microbiology, 168(6), 1997, pp. 532-535
Extracellular proteolytic activity was detected in the haloalkaliphili
c archaeon Natronococcus occultus as the culture reached the stationar
y growth phase. Proteolytic activity was precipitated with ethanol and
subjected to a preliminary characterization. Optimal conditions for a
ctivity were attained at 60 degrees C and 1-2 M NaCl or KCl. Gelatin z
ymography in the presence of 4 M betaine revealed a complex pattern of
active species with apparent molecular masses ranging from 50 to 120
kDa. Experiments performed with inhibitors of the various groups of pr
oteases indicated that the extracellular proteolytic enzymes of N. occ
ultus are of the serine type. Individual protein species showed some d
ifferences in salt and thermal stability.