Pneumococcal neuraminidase.

Lee, L. T. (Columbia University, New York, N.Y.), and C. Howe. Pneumoccal neuraminidase. J. Bacteriol. 91:1418-1426. 1966.-The elaboration of neuraminidase by pneumococci grown under optimal conditions in liquid medium was studied in relation to the bacterial growth cycle. The enzyme was found free in the culture medium in increasing concentration throughout most of the logarithmic phase of growth, at the end of which enzyme concentration had reached a maximum. Only a small fraction of the total neuraminidase was cell-associated at any time. It appears, therefore, that pneumococcal neuraminidase is actively secreted by dividing cells and does not accumulate solely as a result of cellular autolysis. Neuraminidase in cell-free extracts (types I, III, VII, and XIV) was neutralized both by homotypic and by heterotypic antibody, thus demonstrating it to be a group antigen. The enzyme was separable in agar gel electrophoresis from other protein and polysaccharide pneumococcal antigens. Limited immunochemical data suggest that pneumococcal neuraminidase may be of relatively low molecular weight.