COACERVATION PROPERTIES IN SEQUENTIAL POLYPEPTIDE MODELS OF ELASTIN

Abstract
Syntheses of two sequential polypeptides H-(Ala-Pro-Gly-Gly)n-Val-OMe and H-(Ala-Pro-Gly-Val-Gly)n-Val-OMe via the p-nitrophenyl active ester procedure are reported. The two polymers were obtained in good yields and were of large MW, n > 40. These 2 polypeptides were synthesized as analogs of the two coacervating sequential polypeptides, H-(Val-Pro-Gly-Gly)n-Val-OMe, and H-(Val-Pro-Gly-Val-Gly)n-Val-OMe, in which the Val-l residue is replaced by an Ala-l residue. H-(Ala-Pro-Gly-Gly)n-Val-OMe did not coacervate even at as high a temperature as 100.degree. C, and H-(Ala-Pro-Gly-Val-Gly)n-Val-OMe did not coacervate; however, if precipitated irreversibly around 65-70.degree. C. This suggests the critical role of the Val-Pro hydrophobic side chain interaction in coacervation.