Multichain copoly(α‐amino acid). III. Multichain copoly(α‐amino acid) prepared by the reaction of copoly(L‐lysine γ‐methyl‐L‐glutamate) with N‐carboxy anhydride of β‐benzyl L‐aspartate

Graft copolymerization of N ‐carboxy anhydride of β‐benzyl‐ L ‐aspartate onto copoly( L ‐lysine γ‐methyl‐ L ‐glutamate) was carried out in N,N ‐dimethylformaide which contained 3 v/v% of dimethyl sulfoxide to obtain multi‐ N ε ‐poly(β‐benzyl‐ L ‐aspartyl)copoly( L ‐lysine γ‐methyl‐ L gluta mate). The degree of polymerization of the branch chain attained was much influenced by the interval of the grafting sites of the copoly( L ‐lysine γ‐methyl‐ L ‐glutamate). The solvent‐induced two‐step conformational transition of the multichain copoly(α‐amino acid) was observed in the chloroform‐dichloroacetic acid system at 25°C by the ORD technique. The stability of the α‐helical conformation of the backbone polymer chain was decreased by the presence of poly(β‐benzyl‐ L ‐aspartyl) branch chains that could form unstable α‐helical conformations of opposite spirals.