Dissociation of the Specific Protein Precipitate of Antipneumococcus Horse Serum, and a Comparison with a Protein Isolated by Chemical Means from this Immune Serum

[摘要] 1. 1. Afterheating in 0.85 per cent sodium chloride with or without sodium carbonate (Gay and Chickering method), the relationship of protection to nitrogen was found to be approximately the same in precipitate and supernatant fluid of the pneumococcus carbohydrate-protein complex.2. 2. It has been found possible to dissociate the specific precipitate, that is, separate the soluble specific substance from the protein by means of calcium or strontium phosphate.3. 3. The protein thus separated is water-insoluble and salt soluble. In the material studied, it protects mice against one million lethal doses of virulent pneumococci, when the protein content is, in case of Type I, 0.0004 mgm. nitrogen per cubic centimeter, and with Type II 0.004 mgm. per cubic centimeter.4. 4. The protein isolated by dissociation and that isolated by a zinc method are approximately alike in protective titer; both are water-insoluble, but readily soluble in neutral salts, and both alike react in similar fashion in all chemical analyses carried out.5. 5. The nitrogen percentage by weight of the protein obtained by dissociation was with Type I, 14.9 per cent, and with Type II, 15.2 per cent. Three preparations by the zinc method gave respectively 15.7, 15.3 and 15.5 per cent nitrogen.

[学科分类] 生物科学（综合）