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

Antilevan, antidextran, antiteichoic acid, anti-"A" and normal γG, all isolated from a single human, as well as pooled γG and γM, 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 γM- immunoglobulin. No hydroxylysine was found in γG- globulins. These findings probably account for discrepancies in the literature concerning the occurrence of this residue in antibody protein.

STUDIES ON ARTIFICIAL ANTIGENS. II. THE ANTIGENICITY IN GUINEA PIGS OF ARSANILIC ACID CONJUGATES OF COPOLYMERS OF D- OR L-ALPHA-AMINO ACIDS

An effort was made to immunize guinea pigs with arsanilic acid conjugates of copolymers of D- and L-α-amino acids; ASD-GAT and ASL-GAT. An immune response was observed only in the case of ASL-GAT. Antibodies specific for the arsanilic acid hapten were produced which could also react with ASD-GAT or ASGPA. These findings indicate that the proper metabolism of the antigen may be essential to the induction of the immune response.

NOREPINEPHRINE AND 3,4DIHYDROXYPHENETHYLAMINE TURNOVER IN GUINEA PIG BRAIN IN VIVO

By administering C(14)-la-beled tyrosine or H(3)-labeled 3,4-dihy-droxyphenylalanine to guinea pigs it has been possible to achieve sufficient labeling of the norepinephrine and dopamine in the brain to permit measurement of their turnover rates. The half-life of brain dopamine was about 2.5 hours. The half-life of norepinephrine was about 4 hours, suggesting a rate of synthesis of at least 0.03 to 0.04, microg/g per hr or 2.4 microg/day for the whole guinea pig brain.

DROSOPHILA PHENOL OXIDASES

The phenol oxidase systems of Drosophila melanogaster arise from at least four protein components. One A component plus the P preparation yields tyrosinase, while the other two (A(2) and A(3)) yield primarily 3,4-dihydroxyphenylalanine oxidases. Probably the four components represent specialized subunits of the oxidases produced.