Mm. Sexton et al., PURIFICATION AND CHARACTERIZATION OF A PROTEASE FROM PSEUDOMONAS-PSEUDOMALLEI, Canadian journal of microbiology, 40(11), 1994, pp. 903-910
Pseudomonas pseudomallei is the causative agent of melioidosis, a glan
ders-like disease of humans and animals. The pathogenesis of melioidos
is is not well understood, and the role of various extracellular enzym
es produced by P. pseudomallei in the development of this disease is n
ot known. The present studies were designed to purify and characterize
an extracellular protease produced by P. pseudomallei isolates and to
test the hypothesis that this protease may play a role in melioidosis
. The protease was present in culture supernatants as an enzyme with a
molecular weight of 36000 that was optimally active at 60 degrees C a
nd at pH 8.0. The P. pseudomallei protease was shown to be a metalloen
zyme requiring iron for maximal activity, and activity was inhibited i
n the presence of ethylenediaminetetraacetic acid (150 mM). Antibodies
directed against an alkaline protease produced by Pseudomonas aerugin
osa cross-reacted with the P. pseudomallei protease. These data indica
te that the P. pseudomallei protease belongs to the family of alkaline
proteases sensitive to metal chelators. Purified P. pseudomallei prot
ease was capable of digesting a variety of eucaryotic protein substrat
es including immunoglobulins. A P. pseudomallei strain deficient in pr
otease production was shown to be less virulent than the parental stra
in in an animal model of lung infection. These data suggest that this
protease may be a significant pathogenic determinant in infections cau
sed by P. pseudomallei.