Intermolecular association of tetra-(γ-benzyl-L-glutamate)s in ethylene dichloride solutions

✍ Scribed by Toyoko Imae; Shoichi Ikeda

• Publisher: Wiley (John Wiley & Sons)
• Year: 1985
• Tongue: English
• Weight: 763 KB
• Volume: 24
• Category: Article
• ISSN: 0006-3525
• DOI: 10.1002/bip.360240401

✦ Synopsis

Light scattering from ethylene dichloride solutions of tetra-(y-benzyl-cglutamate)s has been measured and their association in solution is examined. One of the peptides is monodisperse o-nitrophenylthio-tetra-(y-benzyl-cglutamate) ethylamide prepared by a stepwise condensation method, and the other is low-molecular-weight poly(y-benzyl-L-glutamate) prepared by the N-carboxyanhydride method with n-hexylamine initiation at [A]/[Il = 4 and fractionated by dissolution in formic acid. Concentrationdependent association of both peptides occurs noncooperatively, without giving critical micelle concentrations. The aggregate sue is small about 23 for the former tetrapeptide and about 7 for the latter polypeptide. While angular dissymmetry is close to unity, light scattering shows anomalous angular dependence, the intensity being symmetrically low with respect to the scattering angle of 90". The observed angular dependence is interpreted in terms of the effect of optical anisotropy of peptide units. Formation of the anisotropic phase in concentrated solutions of these peptides is also examined briefly.