Sedimentation and viscosity studies on the capsular and somatic polysaccharides of pneumococcus Type III.

Sedimentation constants at infinite dilution have been found to be 1.89 and 4.06 for the somatic and capsular polysaccharides, respectively, from pneumococcus Type III. Intrinsic viscosities have been determined for the somatic and capsular polysaccharides of pneumococcus Type III using the Ostwald viscometer. Molecular weights and dimensions have been calculated for the somatic and capsular polysaccharides of pneumococcus Type III assuming the molecules to be prolate ellipsoids of revolution. Values for the somatic polysaccharide are: molecular weight, 26,400; diameter, 0.97 mmicro; and length, 36.18 mmicro. Values for the capsular polysaccharide are: molecular weight, 171,800; diameter, 1.04 mmicro; and length, 177.87 mmicro. The molecular weights were calculated for the somatic and capsular polysaccharides of pneumococcus Type III assuming the molecules to be flexible chains. The value of the molecular weight of the somatic polysaccharide is 31,500 and the value for the molecular weight of the capsular polysaccharide is 267,500. The molecules of both the somatic and capsular polysaccharides exhibit high degrees of asymmetry.