Abstract
The antibodies of an immune animal are associated with the globulin fraction of the serum proteins. Since they are difficult to separate from the serum proteins in a relatively pure form, very few chemical investigations of them have been made. The most recent is that of Hewitt 1 in which are reported the amide-N, mono-amino-N, diamino-N, cystine, tyrosine, and tryptophane of diphtheria toxin-antitoxin floccules. These are compared with the crystalline albumin fraction and the globulin fraction from which the chemical methods used do not permit differentiation.
Careful chemical analysis of the precipitate formed when specific haptens are added to antisera should furnish valuable information since this precipitate contains antibody in the purest form in which it is available. The present investigation is of Type II pneumococcus specific precipitate furnished by Dr. M. Heidelberger and Dr. F. E. Kendall of Columbia University, to whom I wish to express my appreciation. The precipitate contains about 5% of the specific carbohydrate, and the analytical values have not been corrected for this. Analyses of other specific precipitates are in progress.
The specific precipitates were obtained, purified and dried in the usual manner of preparation of protein precipitates by filtration, washing with water, alcohol, and ether and subsequently placing in a vacuum desiccator over some drying agent. Two samples of the white powder thus obtained were analyzed by the general chemical methods of protein analysis in use in this laboratory. 2 The analytical values obtained are summarized in Table I. All values reported are averages of duplicate analyses for the 2 samples except the isolation values obtained for arginine, histidine, lysine, glutamic acid and aspartic acid.
The values found agree in a general way with those reported for serum globulin but before specific comparisons can be made more careful analyses must be carried out on highly purified fractions of the serum globulins, if possible from the same animals from which the specific precipitates have been obtained.
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