Metabolism of Isomeric Synthetic Polypeptides

Abstract

PREVIOUS investigations¹ demonstrated that a synthetic polypeptide containing D-glutamic acid, D-lysine and D-tyrosine is capable of eliciting an antibody response in rabbits: poly D-Glu⁵⁵D-Lys³⁹D-Tyr^6* elicited an average of 26 ± 33 µg Ab N/ml. in 13/17 animals, whereas its L-counterpart, poly Glu⁵⁶Lys³⁸Tyr⁶, elicited 91 ± 52 µg Ab N/ml. in 38/38 animals. In view of this finding, we undertook to determine whether the D-amino-acid polypeptide was capable of being degraded in vivo. In addition, we planned to explore the metabolism of another L-amino-acid counterpart of the D-polymer, poly Glu⁵⁸Lys³⁶Tyr⁶ (No. 2), both as a control for the behaviour of the D-polymer and also to examine further some of the anomalous findings of our previous metabolic study on synthetic polypeptides².