Abstract
To make a comparison of some of the various polymerization methods, poly‐γ‐D‐and L‐glutamylglycine were synthesized through the mixed anhydride, carbodiimide, and pentachlorophenyl active ester methods. This last method proved to be best, on the basis of weight‐average molecular weights (w). A detailed study was also carried out to determine the optimum conditions for this method. The w, values of the polymers were determined by the sedimentation equilibrium method; it was found that the pentachlorophenyl active ester gave w values of up to 11, 500 but the mixed anhydride and carbodiimide methods gave w, values of only about 1000. Tests with rabbit antianthrax immune serum showed that neither D‐ nor L‐isomer precipitated with the antiserum, but that, both were able to inhibit the precipitation of the antiserum by anthrax polypeptide. In addition, the D‐polymer gave more inhibition than the L, which would indicate a specificity of the antibody for D‐glutamic acid residues.
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