FORMATION OF HEMOLYSIN BY STRAINS OF PSEUDOMONAS AERUGINOSA

Abstract

Hemolysin is formed in sonic extracts of cells of Pseudomonas aeruginosa by the action of a heat-labile substance, probably an intracellular "release" enzyme, on a substrate from the disrupted cell. The substrate and most of the hemolysin released can be sedimented by high-speed centrifugation. Hemolysin-negative strains appear to possess no release enzyme but do contain the substrate since addition of particulate matter to extracts of hemolysin-positive cells increases the rate and extent of hemolysin formation. The rate of hemolysin release in sonic extracts is strongly influenced by the concentration of the two reactants, and minor dilution abolishes all activity. There is only a small amount of release enzyme and substrate present in 24-h cells but increasingly greater amounts appear in extracts of 48- and 72-h cells. The hemolysin-forming system is sensitive to heat and is inactivated in 2 min at 100°. Treatment of particulate matter with lysozyme plus EDTA does not reduce the amount of hemolysin released by subsequent exposure of the particles to the release enzyme present in fresh sonic extract.