Properties of purified pneumococcal hemolysin.

With a purified preparation of pneumococcal hemolysin, a sigmoid relationship was found to exist between lysin concentration and hemolytic activity. Hemolysis was inhibited by a high ratio of erythrocytes to lysin, suggesting a multi-hit mechanism of action. Reaction rate decreased rapidly with time, possibly due to competition between ghosts and unlysed erythrocytes for fixation of lysin. The effects of pH and various agents on the processes of lysin adsorption and hemoglobin release were determined. The pneumococcal preparation did not possess nicotinamide adenine dinucleotide glycohydrolase activity.