Extracellular Streptococcal Neuraminidase

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Abstract
Extracellular neuraminidase activity was consistently present when the streptococcal cultures were grown in Todd-Hewitt broth without any additions. Adding glucose (2%) during growth inhibited the expression of enzyme activity completely, and the addition of solid CaCO3 did not prevent the inhibition. Enzyme activity in anaerobic cultures was from 1-5 times higher than in aerobic cultures. Storage at 5[degree]C did not diminish activity; dialysis against dilute phosphate buffer increased activity; addition of Ca++ did not increase activity; EDTA up to 2 mM markedly decreased activity; the activity was pH dependent; heating at 56t for 15 min. destroyed 90% of the activity; addition of large amounts of N-acetylneuraminic acid did not inhibit activity; no activity was found in cell-free extracts of cells from 16 hr. cultures, but their supernantant fluids were inactive and enzymes degrading N-acetylneuraminic acid were absent in 11 tested strains.