SYNTHESIS AND CIRCULAR DICHROIC AND PHOTORESPONSIVE PROPERTIES OF A GRAFT COPOLYMER CONTAINING AN AZOAROMATIC POLYPEPTIDE BRANCH AND ITS MEMBRANE

Graft copolymers composed of a photoresponsive copolypeptide branch from β-benzyl L-as-partate and β -p-phenylazobenzyl L-aspartate (C1Azo), attached to a poly(2-hydroxyethyl methacrylate) (PHEMA) backbone, were newly synthesized. The graft copolymers exhibited different circular dichroic properties in the solution in a mixture of 1,2-dichloroethane (DCE) and methanol from the corresponding branches in DCE. The effect of the addition of trimethyl phosphate to the solution upon the circular dichroisms was also different between the graft copolymers and the corresponding branches. Membranes immersed in DCE showed the same CD curves as those in the solution in a mixture of DCE and methanol. In the case of the graft copolymers containing C1Azo moieties, a photoinduced conformational change of the polypeptide chains was observed in the membrane immersed in DCE as well as in the solution. The effect of trimethyl phosphate on the photoinduced conformational change was also observed both in the solution and in the membrane. © 1990, American Chemical Society. All rights reserved.