The chemical composition of pneumococcal C-polysaccharide.

The species-specific C-polysaccharide of the pneumococcus was first described by Tillett, Goebel, and Avery in 1930 (1). The chemical composition was examined by Heidelberger and Kendall (2) and by Goebel et al. (3) ; the latter study showed that the C-polysaccharide contained 4.47% phosphorus, 5.91% nitrogen, 50.6% reducing sugar, 21.8 % hexosamine, and 13.08% acetyl. Detailed information as to the chemical composition of the polysaccharide was not provided by these early studies, however. It was felt that more thorough understanding of the chemistry of the C-polysaccharide might provide increased knowledge of the structure and metabolic activity of the pneumococcus, and might also shed light on the ability of this polysaccharide to combine with and precipitate the C-reactive protein which appears in human sera during infection. The present report will describe investigations which have demonstrated the presence in the C-polysaccharide of amino sugars and amino acids. The chemical composition thus established indicates that the C-polysaccharide originates from the bacterial cell wall. One constituent of the polysaccharide, galactosamine 6-phosphate, has not been found before in bacterial cell walls.