STUDIES ON HUMAN ANTIBODIES. 3. AMINO ACID COMPOSITION OF FOUR ANTIBODIES FROM ONE INDIVIDUAL

Antilevan, antidextran, antiteichoic acid, anti-"A" and normal gammaG, all isolated from a single human, as well as pooled gammaG and gammaM, were analyzed for amino acid content. Differences ranging from 7 to 32 residues were found among these antibodies in glycine, valine, leucine, tyrosine, arginine, lysine, and threonine content. These conspicuous differences in amino acid composition were not correlated with the Gm type of these antibodies. Hydroxylysine was found in two of the four antibodies, antidextran and antiteichoic acid, and in gammaM- immunoglobulin. No hydroxylysine was found in gammaG- globulins. These findings probably account for discrepancies in the literature concerning the occurrence of this residue in antibody protein.