Proteolytic activity of Oidiodendron kalrai

Abstract

The physiochemical characteristics of the intracellular proteolytic enzymes of Oidiodendron kalari, a neuropathogenic fungus, were studied. The organism in the yeast phase was grown in a semisynthetic medium containing 1% tryptone, at 37 degrees C for 48 hr, on a gyrotory shaker. The crude extract was prepared by breaking the cells in a French pressure cell and the proteolytci activity was tested against biological substrates. The cell-free extract hydrolyzed casein, hemoglobin, lactalbumin, gelatin, elastin, collagen and purified rabbit renal basement membrane to various degrees. Optimal proteolytic activity was observed at pH 6 and at 32 degrees C. Calcium and EDTA did not affect the enzymatic activity; however, activity was partially inhibited by sulfhydryl-blocking agents and by heat-inactivated horse, calf, and human serum. The extract was totally inactivated by exposure to a temperature of 70 degrees C for 60 min. Storage at -76 degrees C or -15 degrees C for 6 months or at 4 degrees C for 4 weeks did not affect protease activity.

Comparative biochemistry of the proteinases of eucaryotic microorganisms.

“…Two isolates of Trichosporon sp. (94,346) and the neuropathogenic fungus Oidiodendron kalrai (45) were reported to have intracellular enzymes optimally active at pH 6. An elastase activity of the dermatophytic fungus Nannizzia fulva, active at pH 8, was inhibited by p-chloromercuribenzoate and iodoacetate but was not enhanced by either cysteine or EDTA (274).…”