Hh. Kong et al., Purification and characterization of a secretory serine proteinase of Acanthamoeba healyi isolated from GAE, J PARASITOL, 86(1), 2000, pp. 12-17
We purified and characterized a serine proteinase secreted by Acanthamoeba
healyi to evaluate it as a possible virulence factor in the pathogenesis of
granulomatous amoebic encephalitis (GAE). Ammonium sulfate precipitated cu
lture supernatant of A. healyi OC-3A strain was purified by chromatography
on CM-Sepharose, Sephacryl-S200, and Q-2 anion-exchange columns. The purifi
ed 33-kDa enzyme had a pH optimum of 8.0 and a temperature optimum of 40 C.
Phenylmethyl-sulfonylfluoride and diisopropyl fluorophosphate, serine prot
einase inhibitors, diminished activity of the enzyme to near zero. In addit
ion to types I and IV collagen and fibronectin, the main components of the
extracellular matrix, other proteins such as fibrinogen, IgG, IgA, albumin,
and hemoglobin were also degraded by the enzyme. The broad substrate speci
ficity of this secreted serine proteinase suggests that it may play an impo
rtant role in pathogenesis of GAE by A. healyi.